diff --git a/core/common/src/test/java/org/onosproject/store/trivial/DefaultTopology.java b/core/common/src/test/java/org/onosproject/store/trivial/DefaultTopology.java
new file mode 100644
index 0000000..9f436b6
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/DefaultTopology.java
@@ -0,0 +1,492 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+import static org.onlab.graph.GraphPathSearch.ALL_PATHS;
+import static org.onosproject.core.CoreService.CORE_PROVIDER_ID;
+import static org.onosproject.net.Link.State.ACTIVE;
+import static org.onosproject.net.Link.State.INACTIVE;
+import static org.onosproject.net.Link.Type.INDIRECT;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.onlab.graph.DijkstraGraphSearch;
+import org.onlab.graph.GraphPathSearch;
+import org.onlab.graph.GraphPathSearch.Result;
+import org.onlab.graph.TarjanGraphSearch;
+import org.onlab.graph.TarjanGraphSearch.SCCResult;
+import org.onosproject.net.AbstractModel;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DefaultPath;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Link;
+import org.onosproject.net.Path;
+import org.onosproject.net.provider.ProviderId;
+import org.onosproject.net.topology.ClusterId;
+import org.onosproject.net.topology.DefaultTopologyCluster;
+import org.onosproject.net.topology.DefaultTopologyVertex;
+import org.onosproject.net.topology.GraphDescription;
+import org.onosproject.net.topology.LinkWeight;
+import org.onosproject.net.topology.Topology;
+import org.onosproject.net.topology.TopologyCluster;
+import org.onosproject.net.topology.TopologyEdge;
+import org.onosproject.net.topology.TopologyGraph;
+import org.onosproject.net.topology.TopologyVertex;
+
+import com.google.common.base.Supplier;
+import com.google.common.base.Suppliers;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.ImmutableSetMultimap;
+import com.google.common.collect.ImmutableSetMultimap.Builder;
+
+// FIXME: Move to onos-core-common when ready
+/**
+ * Default implementation of the topology descriptor. This carries the backing
+ * topology data.
+ */
+public class DefaultTopology extends AbstractModel implements Topology {
+
+    private static final DijkstraGraphSearch<TopologyVertex, TopologyEdge> DIJKSTRA = new DijkstraGraphSearch<>();
+    private static final TarjanGraphSearch<TopologyVertex, TopologyEdge> TARJAN = new TarjanGraphSearch<>();
+
+    private final long time;
+    private final long creationTime;
+    private final long computeCost;
+    private final TopologyGraph graph;
+
+    private final LinkWeight weight;
+    private final Supplier<SCCResult<TopologyVertex, TopologyEdge>> clusterResults;
+    private final Supplier<ImmutableMap<ClusterId, TopologyCluster>> clusters;
+    private final Supplier<ImmutableSet<ConnectPoint>> infrastructurePoints;
+    private final Supplier<ImmutableSetMultimap<ClusterId, ConnectPoint>> broadcastSets;
+
+    private final Supplier<ClusterIndexes> clusterIndexes;
+
+    /**
+     * Creates a topology descriptor attributed to the specified provider.
+     *
+     * @param providerId
+     *            identity of the provider
+     * @param description
+     *            data describing the new topology
+     */
+    DefaultTopology(ProviderId providerId, GraphDescription description) {
+        super(providerId);
+        this.time = description.timestamp();
+        this.creationTime = description.creationTime();
+
+        // Build the graph
+        this.graph = new DefaultTopologyGraph(description.vertexes(),
+                description.edges());
+
+        this.clusterResults = Suppliers.memoize(() -> searchForClusters());
+        this.clusters = Suppliers.memoize(() -> buildTopologyClusters());
+
+        this.clusterIndexes = Suppliers.memoize(() -> buildIndexes());
+
+        this.weight = new HopCountLinkWeight(graph.getVertexes().size());
+        this.broadcastSets = Suppliers.memoize(() -> buildBroadcastSets());
+        this.infrastructurePoints = Suppliers
+                .memoize(() -> findInfrastructurePoints());
+        this.computeCost = Math.max(0, System.nanoTime() - time);
+    }
+
+    @Override
+    public long time() {
+        return time;
+    }
+
+    @Override
+    public long creationTime() {
+        return creationTime;
+    }
+
+    @Override
+    public long computeCost() {
+        return computeCost;
+    }
+
+    @Override
+    public int clusterCount() {
+        return clusters.get().size();
+    }
+
+    @Override
+    public int deviceCount() {
+        return graph.getVertexes().size();
+    }
+
+    @Override
+    public int linkCount() {
+        return graph.getEdges().size();
+    }
+
+    private ImmutableMap<DeviceId, TopologyCluster> clustersByDevice() {
+        return clusterIndexes.get().clustersByDevice;
+    }
+
+    private ImmutableSetMultimap<TopologyCluster, DeviceId> devicesByCluster() {
+        return clusterIndexes.get().devicesByCluster;
+    }
+
+    private ImmutableSetMultimap<TopologyCluster, Link> linksByCluster() {
+        return clusterIndexes.get().linksByCluster;
+    }
+
+    /**
+     * Returns the backing topology graph.
+     *
+     * @return topology graph
+     */
+    TopologyGraph getGraph() {
+        return graph;
+    }
+
+    /**
+     * Returns the set of topology clusters.
+     *
+     * @return set of clusters
+     */
+    Set<TopologyCluster> getClusters() {
+        return ImmutableSet.copyOf(clusters.get().values());
+    }
+
+    /**
+     * Returns the specified topology cluster.
+     *
+     * @param clusterId cluster identifier
+     *
+     * @return topology cluster
+     */
+    TopologyCluster getCluster(ClusterId clusterId) {
+        return clusters.get().get(clusterId);
+    }
+
+    /**
+     * Returns the topology cluster that contains the given device.
+     *
+     * @param deviceId device identifier
+     *
+     * @return topology cluster
+     */
+    TopologyCluster getCluster(DeviceId deviceId) {
+        return clustersByDevice().get(deviceId);
+    }
+
+    /**
+     * Returns the set of cluster devices.
+     *
+     * @param cluster topology cluster
+     *
+     * @return cluster devices
+     */
+    Set<DeviceId> getClusterDevices(TopologyCluster cluster) {
+        return devicesByCluster().get(cluster);
+    }
+
+    /**
+     * Returns the set of cluster links.
+     *
+     * @param cluster topology cluster
+     *
+     * @return cluster links
+     */
+    Set<Link> getClusterLinks(TopologyCluster cluster) {
+        return linksByCluster().get(cluster);
+    }
+
+    /**
+     * Indicates whether the given point is an infrastructure link end-point.
+     *
+     * @param connectPoint connection point
+     *
+     * @return true if infrastructure
+     */
+    boolean isInfrastructure(ConnectPoint connectPoint) {
+        return infrastructurePoints.get().contains(connectPoint);
+    }
+
+    /**
+     * Indicates whether the given point is part of a broadcast set.
+     *
+     * @param connectPoint connection point
+     *
+     * @return true if in broadcast set
+     */
+    boolean isBroadcastPoint(ConnectPoint connectPoint) {
+        // Any non-infrastructure, i.e. edge points are assumed to be OK.
+        if (!isInfrastructure(connectPoint)) {
+            return true;
+        }
+
+        // Find the cluster to which the device belongs.
+        TopologyCluster cluster = clustersByDevice().get(connectPoint.deviceId());
+        if (cluster == null) {
+            throw new IllegalArgumentException("No cluster found for device "
+                    + connectPoint.deviceId());
+        }
+
+        // If the broadcast set is null or empty, or if the point explicitly
+        // belongs to it, return true;
+        Set<ConnectPoint> points = broadcastSets.get().get(cluster.id());
+        return (points == null) || points.isEmpty() || points.contains(connectPoint);
+    }
+
+    /**
+     * Returns the size of the cluster broadcast set.
+     *
+     * @param clusterId cluster identifier
+     *
+     * @return size of the cluster broadcast set
+     */
+    int broadcastSetSize(ClusterId clusterId) {
+        return broadcastSets.get().get(clusterId).size();
+    }
+
+    /**
+     * Returns the set of pre-computed shortest paths between source and
+     * destination devices.
+     *
+     * @param src source device
+     *
+     * @param dst destination device
+     *
+     * @return set of shortest paths
+     */
+    Set<Path> getPaths(DeviceId src, DeviceId dst) {
+        return getPaths(src, dst, null);
+    }
+
+    /**
+     * Computes on-demand the set of shortest paths between source and
+     * destination devices.
+     *
+     * @param src source device
+     *
+     * @param dst destination device
+     *
+     * @param weight link weight function
+     *
+     * @return set of shortest paths
+     */
+    Set<Path> getPaths(DeviceId src, DeviceId dst, LinkWeight weight) {
+        final DefaultTopologyVertex srcV = new DefaultTopologyVertex(src);
+        final DefaultTopologyVertex dstV = new DefaultTopologyVertex(dst);
+        Set<TopologyVertex> vertices = graph.getVertexes();
+        if (!vertices.contains(srcV) || !vertices.contains(dstV)) {
+            // src or dst not part of the current graph
+            return ImmutableSet.of();
+        }
+
+        GraphPathSearch.Result<TopologyVertex, TopologyEdge> result =
+                DIJKSTRA.search(graph, srcV, dstV, weight, ALL_PATHS);
+        ImmutableSet.Builder<Path> builder = ImmutableSet.builder();
+        for (org.onlab.graph.Path<TopologyVertex, TopologyEdge> path : result.paths()) {
+            builder.add(networkPath(path));
+        }
+        return builder.build();
+    }
+
+    // Converts graph path to a network path with the same cost.
+    private Path networkPath(org.onlab.graph.Path<TopologyVertex, TopologyEdge> path) {
+        List<Link> links = new ArrayList<>();
+        for (TopologyEdge edge : path.edges()) {
+            links.add(edge.link());
+        }
+        return new DefaultPath(CORE_PROVIDER_ID, links, path.cost());
+    }
+
+    // Searches for SCC clusters in the network topology graph using Tarjan
+    // algorithm.
+    private SCCResult<TopologyVertex, TopologyEdge> searchForClusters() {
+        return TARJAN.search(graph, new NoIndirectLinksWeight());
+    }
+
+    // Builds the topology clusters and returns the id-cluster bindings.
+    private ImmutableMap<ClusterId, TopologyCluster> buildTopologyClusters() {
+        ImmutableMap.Builder<ClusterId, TopologyCluster> clusterBuilder = ImmutableMap.builder();
+        SCCResult<TopologyVertex, TopologyEdge> results = clusterResults.get();
+        // Extract both vertexes and edges from the results; the lists form
+        // pairs along the same index.
+        List<Set<TopologyVertex>> clusterVertexes = results.clusterVertexes();
+        List<Set<TopologyEdge>> clusterEdges = results.clusterEdges();
+
+        // Scan over the lists and create a cluster from the results.
+        for (int i = 0, n = results.clusterCount(); i < n; i++) {
+            Set<TopologyVertex> vertexSet = clusterVertexes.get(i);
+            Set<TopologyEdge> edgeSet = clusterEdges.get(i);
+
+            ClusterId cid = ClusterId.clusterId(i);
+            DefaultTopologyCluster cluster = new DefaultTopologyCluster(cid,
+                                                                        vertexSet.size(),
+                                                                        edgeSet.size(),
+                                                                        findRoot(vertexSet));
+            clusterBuilder.put(cid, cluster);
+        }
+        return clusterBuilder.build();
+    }
+
+    // Finds the vertex whose device id is the lexicographical minimum in the
+    // specified set.
+    private TopologyVertex findRoot(Set<TopologyVertex> vertexSet) {
+        TopologyVertex minVertex = null;
+        for (TopologyVertex vertex : vertexSet) {
+            if ((minVertex == null) || (minVertex.deviceId().toString()
+                    .compareTo(minVertex.deviceId().toString()) < 0)) {
+                minVertex = vertex;
+            }
+        }
+        return minVertex;
+    }
+
+    // Processes a map of broadcast sets for each cluster.
+    private ImmutableSetMultimap<ClusterId, ConnectPoint> buildBroadcastSets() {
+        Builder<ClusterId, ConnectPoint> builder = ImmutableSetMultimap.builder();
+        for (TopologyCluster cluster : clusters.get().values()) {
+            addClusterBroadcastSet(cluster, builder);
+        }
+        return builder.build();
+    }
+
+    // Finds all broadcast points for the cluster. These are those connection
+    // points which lie along the shortest paths between the cluster root and
+    // all other devices within the cluster.
+    private void addClusterBroadcastSet(TopologyCluster cluster, Builder<ClusterId, ConnectPoint> builder) {
+        // Use the graph root search results to build the broadcast set.
+        Result<TopologyVertex, TopologyEdge> result =
+                DIJKSTRA.search(graph, cluster.root(), null, weight, 1);
+        for (Map.Entry<TopologyVertex, Set<TopologyEdge>> entry : result.parents().entrySet()) {
+            TopologyVertex vertex = entry.getKey();
+
+            // Ignore any parents that lead outside the cluster.
+            if (clustersByDevice().get(vertex.deviceId()) != cluster) {
+                continue;
+            }
+
+            // Ignore any back-link sets that are empty.
+            Set<TopologyEdge> parents = entry.getValue();
+            if (parents.isEmpty()) {
+                continue;
+            }
+
+            // Use the first back-link source and destinations to add to the
+            // broadcast set.
+            Link link = parents.iterator().next().link();
+            builder.put(cluster.id(), link.src());
+            builder.put(cluster.id(), link.dst());
+        }
+    }
+
+    // Collects and returns an set of all infrastructure link end-points.
+    private ImmutableSet<ConnectPoint> findInfrastructurePoints() {
+        ImmutableSet.Builder<ConnectPoint> builder = ImmutableSet.builder();
+        for (TopologyEdge edge : graph.getEdges()) {
+            builder.add(edge.link().src());
+            builder.add(edge.link().dst());
+        }
+        return builder.build();
+    }
+
+    // Builds cluster-devices, cluster-links and device-cluster indexes.
+    private ClusterIndexes buildIndexes() {
+        // Prepare the index builders
+        ImmutableMap.Builder<DeviceId, TopologyCluster> clusterBuilder =
+                ImmutableMap.builder();
+        ImmutableSetMultimap.Builder<TopologyCluster, DeviceId> devicesBuilder =
+                ImmutableSetMultimap.builder();
+        ImmutableSetMultimap.Builder<TopologyCluster, Link> linksBuilder =
+                ImmutableSetMultimap.builder();
+
+        // Now scan through all the clusters
+        for (TopologyCluster cluster : clusters.get().values()) {
+            int i = cluster.id().index();
+
+            // Scan through all the cluster vertexes.
+            for (TopologyVertex vertex : clusterResults.get().clusterVertexes().get(i)) {
+                devicesBuilder.put(cluster, vertex.deviceId());
+                clusterBuilder.put(vertex.deviceId(), cluster);
+            }
+
+            // Scan through all the cluster edges.
+            for (TopologyEdge edge : clusterResults.get().clusterEdges().get(i)) {
+                linksBuilder.put(cluster, edge.link());
+            }
+        }
+
+        // Finalize all indexes.
+        return new ClusterIndexes(clusterBuilder.build(),
+                devicesBuilder.build(), linksBuilder.build());
+    }
+
+    // Link weight for measuring link cost as hop count with indirect links
+    // being as expensive as traversing the entire graph to assume the worst.
+    private static class HopCountLinkWeight implements LinkWeight {
+        private final int indirectLinkCost;
+
+        HopCountLinkWeight(int indirectLinkCost) {
+            this.indirectLinkCost = indirectLinkCost;
+        }
+
+        @Override
+        public double weight(TopologyEdge edge) {
+            // To force preference to use direct paths first, make indirect
+            // links as expensive as the linear vertex traversal.
+            return edge.link().state() ==
+                    ACTIVE ? (edge.link().type() ==
+                    INDIRECT ? indirectLinkCost : 1) : -1;
+        }
+    }
+
+    // Link weight for preventing traversal over indirect links.
+    private static class NoIndirectLinksWeight implements LinkWeight {
+        @Override
+        public double weight(TopologyEdge edge) {
+            return (edge.link().state() == INACTIVE)
+                    || (edge.link().type() == INDIRECT) ? -1 : 1;
+        }
+    }
+
+    static final class ClusterIndexes {
+        final ImmutableMap<DeviceId, TopologyCluster> clustersByDevice;
+        final ImmutableSetMultimap<TopologyCluster, DeviceId> devicesByCluster;
+        final ImmutableSetMultimap<TopologyCluster, Link> linksByCluster;
+
+        public ClusterIndexes(
+                ImmutableMap<DeviceId, TopologyCluster> clustersByDevice,
+                ImmutableSetMultimap<TopologyCluster, DeviceId> devicesByCluster,
+                ImmutableSetMultimap<TopologyCluster, Link> linksByCluster) {
+            this.clustersByDevice = clustersByDevice;
+            this.devicesByCluster = devicesByCluster;
+            this.linksByCluster = linksByCluster;
+        }
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this)
+                .add("time", time)
+                .add("created", creationTime)
+                .add("computeCost", computeCost)
+                .add("clusters", clusterCount())
+                .add("devices", deviceCount())
+                .add("links", linkCount()).toString();
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/DefaultTopologyGraph.java b/core/common/src/test/java/org/onosproject/store/trivial/DefaultTopologyGraph.java
new file mode 100644
index 0000000..610d724
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/DefaultTopologyGraph.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import org.onlab.graph.AdjacencyListsGraph;
+import org.onosproject.net.topology.TopologyEdge;
+import org.onosproject.net.topology.TopologyGraph;
+import org.onosproject.net.topology.TopologyVertex;
+
+import java.util.Set;
+
+/**
+ * Default implementation of an immutable topology graph based on a generic
+ * implementation of adjacency lists graph.
+ */
+public class DefaultTopologyGraph
+        extends AdjacencyListsGraph<TopologyVertex, TopologyEdge>
+        implements TopologyGraph {
+
+    /**
+     * Creates a topology graph comprising of the specified vertexes and edges.
+     *
+     * @param vertexes set of graph vertexes
+     * @param edges    set of graph edges
+     */
+    public DefaultTopologyGraph(Set<TopologyVertex> vertexes, Set<TopologyEdge> edges) {
+        super(vertexes, edges);
+    }
+
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/DefaultTopologyTest.java b/core/common/src/test/java/org/onosproject/store/trivial/DefaultTopologyTest.java
new file mode 100644
index 0000000..3ff340a
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/DefaultTopologyTest.java
@@ -0,0 +1,141 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.packet.ChassisId;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DefaultDevice;
+import org.onosproject.net.DefaultLink;
+import org.onosproject.net.Device;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Link;
+import org.onosproject.net.Path;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.provider.ProviderId;
+import org.onosproject.net.topology.ClusterId;
+import org.onosproject.net.topology.DefaultGraphDescription;
+import org.onosproject.net.topology.GraphDescription;
+import org.onosproject.net.topology.LinkWeight;
+import org.onosproject.net.topology.TopologyCluster;
+
+import java.util.Set;
+
+import static com.google.common.collect.ImmutableSet.of;
+import static org.junit.Assert.*;
+import static org.onosproject.net.DeviceId.deviceId;
+import static org.onosproject.net.PortNumber.portNumber;
+
+/**
+ * Test of the default topology implementation.
+ */
+public class DefaultTopologyTest {
+
+    public static final ProviderId PID = new ProviderId("of", "foo.bar");
+
+    public static final DeviceId D1 = deviceId("of:1");
+    public static final DeviceId D2 = deviceId("of:2");
+    public static final DeviceId D3 = deviceId("of:3");
+    public static final DeviceId D4 = deviceId("of:4");
+    public static final DeviceId D5 = deviceId("of:5");
+
+    public static final PortNumber P1 = portNumber(1);
+    public static final PortNumber P2 = portNumber(2);
+
+    public static final LinkWeight WEIGHT = edge ->
+            edge.src().deviceId().equals(D4) || edge.dst().deviceId().equals(D4)
+                    ? 2.0 : 1.0;
+
+    private DefaultTopology dt;
+
+    @Before
+    public void setUp() {
+        long now = System.currentTimeMillis();
+        Set<Device> devices = of(device("1"), device("2"),
+                                 device("3"), device("4"),
+                                 device("5"));
+        Set<Link> links = of(link("1", 1, "2", 1), link("2", 1, "1", 1),
+                             link("3", 2, "2", 2), link("2", 2, "3", 2),
+                             link("1", 3, "4", 3), link("4", 3, "1", 3),
+                             link("3", 4, "4", 4), link("4", 4, "3", 4));
+        GraphDescription graphDescription =
+                new DefaultGraphDescription(now, devices, links);
+
+        dt = new DefaultTopology(PID, graphDescription);
+        assertEquals("incorrect supplier", PID, dt.providerId());
+        assertEquals("incorrect time", now, dt.time());
+        assertEquals("incorrect device count", 5, dt.deviceCount());
+        assertEquals("incorrect link count", 8, dt.linkCount());
+        assertEquals("incorrect cluster count", 2, dt.clusterCount());
+        assertEquals("incorrect broadcast set size", 6,
+                     dt.broadcastSetSize(ClusterId.clusterId(0)));
+    }
+
+    @Test
+    public void pathRelated() {
+        Set<Path> paths = dt.getPaths(D1, D2);
+        assertEquals("incorrect path count", 1, paths.size());
+
+        paths = dt.getPaths(D1, D3);
+        assertEquals("incorrect path count", 2, paths.size());
+
+        paths = dt.getPaths(D1, D5);
+        assertTrue("no paths expected", paths.isEmpty());
+
+        paths = dt.getPaths(D1, D3, WEIGHT);
+        assertEquals("incorrect path count", 1, paths.size());
+    }
+
+    @Test
+    public void pointRelated() {
+        assertTrue("should be infrastructure point",
+                   dt.isInfrastructure(new ConnectPoint(D1, P1)));
+        assertFalse("should not be infrastructure point",
+                    dt.isInfrastructure(new ConnectPoint(D1, P2)));
+    }
+
+    @Test
+    public void clusterRelated() {
+        Set<TopologyCluster> clusters = dt.getClusters();
+        assertEquals("incorrect cluster count", 2, clusters.size());
+
+        TopologyCluster c = dt.getCluster(D1);
+        Set<DeviceId> devs = dt.getClusterDevices(c);
+        assertEquals("incorrect cluster device count", 4, devs.size());
+        assertTrue("cluster should contain D2", devs.contains(D2));
+        assertFalse("cluster should not contain D5", devs.contains(D5));
+    }
+
+    // Short-hand for creating a link.
+    public static Link link(String src, int sp, String dst, int dp) {
+        return new DefaultLink(PID, new ConnectPoint(did(src), portNumber(sp)),
+                               new ConnectPoint(did(dst), portNumber(dp)),
+                               Link.Type.DIRECT);
+    }
+
+    // Crates a new device with the specified id
+    public static Device device(String id) {
+        return new DefaultDevice(PID, did(id), Device.Type.SWITCH,
+                                 "mfg", "1.0", "1.1", "1234", new ChassisId());
+    }
+
+    // Short-hand for producing a device id from a string
+    public static DeviceId did(String id) {
+        return deviceId("of:" + id);
+    }
+
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/NoOpClockProviderService.java b/core/common/src/test/java/org/onosproject/store/trivial/NoOpClockProviderService.java
new file mode 100644
index 0000000..739d36f
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/NoOpClockProviderService.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import java.util.Set;
+
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.mastership.MastershipTerm;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.device.DeviceClockProviderService;
+
+import com.google.common.collect.Sets;
+
+/**
+ * Dummy implementation of {@link DeviceClockProviderService}.
+ */
+@Component(immediate = true)
+@Service
+public class NoOpClockProviderService implements DeviceClockProviderService {
+
+    private Set<DeviceId> registerdBefore = Sets.newConcurrentHashSet();
+
+    @Override
+    public void setMastershipTerm(DeviceId deviceId, MastershipTerm term) {
+        registerdBefore.add(deviceId);
+    }
+
+    @Override
+    public boolean isTimestampAvailable(DeviceId deviceId) {
+        return registerdBefore.contains(deviceId);
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/PathKey.java b/core/common/src/test/java/org/onosproject/store/trivial/PathKey.java
new file mode 100644
index 0000000..00d6c9d
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/PathKey.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import org.onosproject.net.DeviceId;
+
+import java.util.Objects;
+
+/**
+ * Key for filing pre-computed paths between source and destination devices.
+ */
+class PathKey {
+    private final DeviceId src;
+    private final DeviceId dst;
+
+    /**
+     * Creates a path key from the given source/dest pair.
+     * @param src source device
+     * @param dst destination device
+     */
+    PathKey(DeviceId src, DeviceId dst) {
+        this.src = src;
+        this.dst = dst;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(src, dst);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof PathKey) {
+            final PathKey other = (PathKey) obj;
+            return Objects.equals(this.src, other.src) && Objects.equals(this.dst, other.dst);
+        }
+        return false;
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleApplicationIdStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleApplicationIdStore.java
new file mode 100644
index 0000000..6e6b958
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleApplicationIdStore.java
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.collect.ImmutableSet;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.ApplicationIdStore;
+import org.onosproject.core.DefaultApplicationId;
+
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Simple implementation of the application ID registry using in-memory
+ * structures.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleApplicationIdStore implements ApplicationIdStore {
+
+    private static final AtomicInteger ID_DISPENSER = new AtomicInteger(1);
+
+    private final Map<Short, DefaultApplicationId> appIds = new ConcurrentHashMap<>();
+    private final Map<String, DefaultApplicationId> appIdsByName = new ConcurrentHashMap<>();
+
+    @Override
+    public Set<ApplicationId> getAppIds() {
+        return ImmutableSet.<ApplicationId>copyOf(appIds.values());
+    }
+
+    @Override
+    public ApplicationId getAppId(Short id) {
+        return appIds.get(id);
+    }
+
+    @Override
+    public ApplicationId getAppId(String name) {
+        return appIdsByName.get(name);
+    }
+
+    @Override
+    public ApplicationId registerApplication(String name) {
+        DefaultApplicationId appId = appIdsByName.get(name);
+        if (appId == null) {
+            short id = (short) ID_DISPENSER.getAndIncrement();
+            appId = new DefaultApplicationId(id, name);
+            appIds.put(id, appId);
+            appIdsByName.put(name, appId);
+        }
+        return appId;
+    }
+
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleApplicationStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleApplicationStore.java
new file mode 100644
index 0000000..d38b801
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleApplicationStore.java
@@ -0,0 +1,170 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.collect.ImmutableSet;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.app.ApplicationDescription;
+import org.onosproject.app.ApplicationEvent;
+import org.onosproject.app.ApplicationState;
+import org.onosproject.app.ApplicationStore;
+import org.onosproject.common.app.ApplicationArchive;
+import org.onosproject.core.Application;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.ApplicationIdStore;
+import org.onosproject.core.DefaultApplication;
+import org.onosproject.core.Permission;
+import org.slf4j.Logger;
+
+import java.io.InputStream;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+import static org.onosproject.app.ApplicationEvent.Type.*;
+import static org.onosproject.app.ApplicationState.ACTIVE;
+import static org.onosproject.app.ApplicationState.INSTALLED;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Manages inventory of network control applications.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleApplicationStore extends ApplicationArchive implements ApplicationStore {
+
+    private final Logger log = getLogger(getClass());
+
+    // App inventory & states
+    private final ConcurrentMap<ApplicationId, DefaultApplication> apps = new ConcurrentHashMap<>();
+    private final ConcurrentMap<ApplicationId, ApplicationState> states = new ConcurrentHashMap<>();
+    private final ConcurrentMap<ApplicationId, Set<Permission>> permissions = new ConcurrentHashMap<>();
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected ApplicationIdStore idStore;
+
+    @Activate
+    public void activate() {
+        loadFromDisk();
+        log.info("Started");
+    }
+
+    private void loadFromDisk() {
+        for (String name : getApplicationNames()) {
+            ApplicationId appId = idStore.registerApplication(name);
+            ApplicationDescription appDesc = getApplicationDescription(name);
+            DefaultApplication app =
+                    new DefaultApplication(appId, appDesc.version(),
+                                           appDesc.description(), appDesc.origin(),
+                                           appDesc.role(), appDesc.permissions(),
+                                           appDesc.featuresRepo(), appDesc.features());
+            apps.put(appId, app);
+            states.put(appId, isActive(name) ? INSTALLED : ACTIVE);
+            // load app permissions
+        }
+    }
+
+    @Deactivate
+    public void deactivate() {
+        apps.clear();
+        states.clear();
+        permissions.clear();
+        log.info("Stopped");
+    }
+
+    @Override
+    public Set<Application> getApplications() {
+        return ImmutableSet.copyOf(apps.values());
+    }
+
+    @Override
+    public ApplicationId getId(String name) {
+        return idStore.getAppId(name);
+    }
+
+    @Override
+    public Application getApplication(ApplicationId appId) {
+        return apps.get(appId);
+    }
+
+    @Override
+    public ApplicationState getState(ApplicationId appId) {
+        return states.get(appId);
+    }
+
+    @Override
+    public Application create(InputStream appDescStream) {
+        ApplicationDescription appDesc = saveApplication(appDescStream);
+        ApplicationId appId = idStore.registerApplication(appDesc.name());
+        DefaultApplication app =
+                new DefaultApplication(appId, appDesc.version(), appDesc.description(),
+                                       appDesc.origin(), appDesc.role(), appDesc.permissions(),
+                                       appDesc.featuresRepo(), appDesc.features());
+        apps.put(appId, app);
+        states.put(appId, INSTALLED);
+        delegate.notify(new ApplicationEvent(APP_INSTALLED, app));
+        return app;
+    }
+
+    @Override
+    public void remove(ApplicationId appId) {
+        Application app = apps.remove(appId);
+        if (app != null) {
+            states.remove(appId);
+            delegate.notify(new ApplicationEvent(APP_UNINSTALLED, app));
+            purgeApplication(app.id().name());
+        }
+    }
+
+    @Override
+    public void activate(ApplicationId appId) {
+        Application app = apps.get(appId);
+        if (app != null) {
+            setActive(appId.name());
+            states.put(appId, ACTIVE);
+            delegate.notify(new ApplicationEvent(APP_ACTIVATED, app));
+        }
+    }
+
+    @Override
+    public void deactivate(ApplicationId appId) {
+        Application app = apps.get(appId);
+        if (app != null) {
+            clearActive(appId.name());
+            states.put(appId, INSTALLED);
+            delegate.notify(new ApplicationEvent(APP_DEACTIVATED, app));
+        }
+    }
+
+    @Override
+    public Set<Permission> getPermissions(ApplicationId appId) {
+        return permissions.get(appId);
+    }
+
+    @Override
+    public void setPermissions(ApplicationId appId, Set<Permission> permissions) {
+        Application app = getApplication(appId);
+        if (app != null) {
+            this.permissions.put(appId, permissions);
+            delegate.notify(new ApplicationEvent(APP_PERMISSIONS_CHANGED, app));
+        }
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleApplicationStoreTest.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleApplicationStoreTest.java
new file mode 100644
index 0000000..27996e5
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleApplicationStoreTest.java
@@ -0,0 +1,157 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.collect.ImmutableSet;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.util.Tools;
+import org.onosproject.app.ApplicationEvent;
+import org.onosproject.app.ApplicationStoreDelegate;
+import org.onosproject.common.app.ApplicationArchive;
+import org.onosproject.core.Application;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.Permission;
+import org.onosproject.core.ApplicationIdStoreAdapter;
+import org.onosproject.core.DefaultApplicationId;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Random;
+
+import static org.junit.Assert.assertEquals;
+import static org.onosproject.app.ApplicationEvent.Type.APP_INSTALLED;
+import static org.onosproject.app.ApplicationEvent.Type.APP_DEACTIVATED;
+import static org.onosproject.app.ApplicationEvent.Type.APP_ACTIVATED;
+import static org.onosproject.app.ApplicationEvent.Type.APP_UNINSTALLED;
+import static org.onosproject.app.ApplicationEvent.Type.APP_PERMISSIONS_CHANGED;
+import static org.onosproject.app.ApplicationState.ACTIVE;
+import static org.onosproject.app.ApplicationState.INSTALLED;
+
+/**
+ * Test of the trivial application store implementation.
+ */
+public class SimpleApplicationStoreTest {
+
+    static final String ROOT = "/tmp/app-junit/";
+    static final String STORE = ROOT + new Random().nextInt(1000) + "/foo";
+
+    private TestApplicationStore store = new TestApplicationStore();
+    private TestDelegate delegate = new TestDelegate();
+    private static final Object LOCK = new Object();
+
+    @Before
+    public void setUp() {
+        store.idStore = new TestIdStore();
+        store.setRootPath(STORE);
+        store.setDelegate(delegate);
+        store.activate();
+    }
+
+    @After
+    public void tearDown() throws IOException {
+        if (new File(ROOT).exists()) {
+            Tools.removeDirectory(ROOT);
+        }
+        store.deactivate();
+    }
+
+    private Application createTestApp() {
+        synchronized (LOCK) {
+            return store.create(ApplicationArchive.class.getResourceAsStream("app.zip"));
+        }
+    }
+
+    @Test
+    public void create() {
+        Application app = createTestApp();
+        assertEquals("incorrect name", "org.foo.app", app.id().name());
+        assertEquals("incorrect app count", 1, store.getApplications().size());
+        assertEquals("incorrect app", app, store.getApplication(app.id()));
+        assertEquals("incorrect app state", INSTALLED, store.getState(app.id()));
+        assertEquals("incorrect event type", APP_INSTALLED, delegate.event.type());
+        assertEquals("incorrect event app", app, delegate.event.subject());
+    }
+
+    @Test
+    public void remove() {
+        Application app = createTestApp();
+        store.remove(app.id());
+        assertEquals("incorrect app count", 0, store.getApplications().size());
+        assertEquals("incorrect event type", APP_UNINSTALLED, delegate.event.type());
+        assertEquals("incorrect event app", app, delegate.event.subject());
+    }
+
+    @Test
+    public void activate() {
+        Application app = createTestApp();
+        store.activate(app.id());
+        assertEquals("incorrect app count", 1, store.getApplications().size());
+        assertEquals("incorrect app state", ACTIVE, store.getState(app.id()));
+        assertEquals("incorrect event type", APP_ACTIVATED, delegate.event.type());
+        assertEquals("incorrect event app", app, delegate.event.subject());
+    }
+
+    @Test
+    public void deactivate() {
+        Application app = createTestApp();
+        store.deactivate(app.id());
+        assertEquals("incorrect app count", 1, store.getApplications().size());
+        assertEquals("incorrect app state", INSTALLED, store.getState(app.id()));
+        assertEquals("incorrect event type", APP_DEACTIVATED, delegate.event.type());
+        assertEquals("incorrect event app", app, delegate.event.subject());
+    }
+
+    @Test
+    public void permissions() {
+        Application app = createTestApp();
+        ImmutableSet<Permission> permissions = ImmutableSet.of(Permission.FLOWRULE_WRITE);
+        store.setPermissions(app.id(), permissions);
+        assertEquals("incorrect app perms", 1, store.getPermissions(app.id()).size());
+        assertEquals("incorrect app state", INSTALLED, store.getState(app.id()));
+        assertEquals("incorrect event type", APP_PERMISSIONS_CHANGED, delegate.event.type());
+        assertEquals("incorrect event app", app, delegate.event.subject());
+    }
+
+    private class TestIdStore extends ApplicationIdStoreAdapter {
+        @Override
+        public ApplicationId registerApplication(String name) {
+            return new DefaultApplicationId(1, name);
+        }
+
+        @Override
+        public ApplicationId getAppId(String name) {
+            return new DefaultApplicationId(1, name);
+        }
+    }
+
+    private class TestDelegate implements ApplicationStoreDelegate {
+        private ApplicationEvent event;
+
+        @Override
+        public void notify(ApplicationEvent event) {
+            this.event = event;
+        }
+    }
+
+    private class TestApplicationStore extends SimpleApplicationStore {
+        @Override
+        public void setRootPath(String root) {
+            super.setRootPath(root);
+        }
+    }
+}
\ No newline at end of file
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleClusterStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleClusterStore.java
new file mode 100644
index 0000000..5eea3cc
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleClusterStore.java
@@ -0,0 +1,139 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.collect.ImmutableSet;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.joda.time.DateTime;
+import org.onlab.packet.IpAddress;
+import org.onosproject.cluster.ClusterEvent;
+import org.onosproject.cluster.ClusterStore;
+import org.onosproject.cluster.ClusterStoreDelegate;
+import org.onosproject.cluster.ControllerNode;
+import org.onosproject.cluster.DefaultControllerNode;
+import org.onosproject.cluster.NodeId;
+import org.onosproject.event.EventDeliveryService;
+import org.onosproject.event.ListenerRegistry;
+import org.onosproject.net.intent.Key;
+import org.onosproject.net.intent.PartitionEvent;
+import org.onosproject.net.intent.PartitionEventListener;
+import org.onosproject.net.intent.PartitionService;
+import org.onosproject.store.AbstractStore;
+import org.slf4j.Logger;
+
+import java.util.Set;
+
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Manages inventory of infrastructure devices using trivial in-memory
+ * structures implementation.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleClusterStore
+        extends AbstractStore<ClusterEvent, ClusterStoreDelegate>
+        implements ClusterStore, PartitionService {
+
+    public static final IpAddress LOCALHOST = IpAddress.valueOf("127.0.0.1");
+
+    private final Logger log = getLogger(getClass());
+
+    private ControllerNode instance;
+
+    private final DateTime creationTime = DateTime.now();
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected EventDeliveryService eventDispatcher;
+
+    private ListenerRegistry<PartitionEvent, PartitionEventListener> listenerRegistry;
+
+    @Activate
+    public void activate() {
+        instance = new DefaultControllerNode(new NodeId("local"), LOCALHOST);
+
+        listenerRegistry = new ListenerRegistry<>();
+        eventDispatcher.addSink(PartitionEvent.class, listenerRegistry);
+
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        eventDispatcher.removeSink(PartitionEvent.class);
+        log.info("Stopped");
+    }
+
+
+    @Override
+    public ControllerNode getLocalNode() {
+        return instance;
+    }
+
+    @Override
+    public Set<ControllerNode> getNodes() {
+        return ImmutableSet.of(instance);
+    }
+
+    @Override
+    public ControllerNode getNode(NodeId nodeId) {
+        return instance.id().equals(nodeId) ? instance : null;
+    }
+
+    @Override
+    public ControllerNode.State getState(NodeId nodeId) {
+        return ControllerNode.State.ACTIVE;
+    }
+
+    @Override
+    public DateTime getLastUpdated(NodeId nodeId) {
+        return creationTime;
+    }
+
+    @Override
+    public ControllerNode addNode(NodeId nodeId, IpAddress ip, int tcpPort) {
+        return null;
+    }
+
+    @Override
+    public void removeNode(NodeId nodeId) {
+    }
+
+    @Override
+    public boolean isMine(Key intentKey) {
+        return true;
+    }
+
+    @Override
+    public NodeId getLeader(Key intentKey) {
+        return instance.id();
+    }
+
+    @Override
+    public void addListener(PartitionEventListener listener) {
+        listenerRegistry.addListener(listener);
+    }
+
+    @Override
+    public void removeListener(PartitionEventListener listener) {
+        listenerRegistry.removeListener(listener);
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleComponentConfigStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleComponentConfigStore.java
new file mode 100644
index 0000000..1d8bcd6
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleComponentConfigStore.java
@@ -0,0 +1,62 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.cfg.ComponentConfigEvent;
+import org.onosproject.cfg.ComponentConfigStore;
+import org.onosproject.cfg.ComponentConfigStoreDelegate;
+import org.onosproject.store.AbstractStore;
+import org.slf4j.Logger;
+
+import static org.onosproject.cfg.ComponentConfigEvent.Type.PROPERTY_SET;
+import static org.onosproject.cfg.ComponentConfigEvent.Type.PROPERTY_UNSET;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Manages inventory of component configuration properties.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleComponentConfigStore
+        extends AbstractStore<ComponentConfigEvent, ComponentConfigStoreDelegate>
+        implements ComponentConfigStore {
+
+    private final Logger log = getLogger(getClass());
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        log.info("Stopped");
+    }
+
+    @Override
+    public void setProperty(String componentName, String name, String value) {
+        delegate.notify(new ComponentConfigEvent(PROPERTY_SET, componentName, name, value));
+    }
+
+    @Override
+    public void unsetProperty(String componentName, String name) {
+        delegate.notify(new ComponentConfigEvent(PROPERTY_UNSET, componentName, name, null));
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java
new file mode 100644
index 0000000..f1a6982
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java
@@ -0,0 +1,638 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.FluentIterable;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.net.AnnotationsUtil;
+import org.onosproject.net.DefaultAnnotations;
+import org.onosproject.net.DefaultDevice;
+import org.onosproject.net.DefaultPort;
+import org.onosproject.net.Device;
+import org.onosproject.net.Device.Type;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Port;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.SparseAnnotations;
+import org.onosproject.net.device.DefaultDeviceDescription;
+import org.onosproject.net.device.DefaultPortDescription;
+import org.onosproject.net.device.DeviceDescription;
+import org.onosproject.net.device.DeviceEvent;
+import org.onosproject.net.device.DeviceStore;
+import org.onosproject.net.device.DeviceStoreDelegate;
+import org.onosproject.net.device.PortDescription;
+import org.onosproject.net.device.PortStatistics;
+import org.onosproject.net.provider.ProviderId;
+import org.onosproject.store.AbstractStore;
+import org.onlab.packet.ChassisId;
+import org.onlab.util.NewConcurrentHashMap;
+import org.slf4j.Logger;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Predicates.notNull;
+import static com.google.common.base.Verify.verify;
+import static org.onosproject.net.device.DeviceEvent.Type.*;
+import static org.slf4j.LoggerFactory.getLogger;
+import static org.apache.commons.lang3.concurrent.ConcurrentUtils.createIfAbsentUnchecked;
+import static org.onosproject.net.DefaultAnnotations.union;
+import static org.onosproject.net.DefaultAnnotations.merge;
+
+/**
+ * Manages inventory of infrastructure devices using trivial in-memory
+ * structures implementation.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleDeviceStore
+        extends AbstractStore<DeviceEvent, DeviceStoreDelegate>
+        implements DeviceStore {
+
+    private final Logger log = getLogger(getClass());
+
+    public static final String DEVICE_NOT_FOUND = "Device with ID %s not found";
+
+    // Collection of Description given from various providers
+    private final ConcurrentMap<DeviceId, Map<ProviderId, DeviceDescriptions>>
+            deviceDescs = Maps.newConcurrentMap();
+
+    // Cache of Device and Ports generated by compositing descriptions from providers
+    private final ConcurrentMap<DeviceId, Device> devices = Maps.newConcurrentMap();
+    private final ConcurrentMap<DeviceId, ConcurrentMap<PortNumber, Port>>
+            devicePorts = Maps.newConcurrentMap();
+    private final ConcurrentMap<DeviceId, ConcurrentMap<PortNumber, PortStatistics>>
+            devicePortStats = Maps.newConcurrentMap();
+
+    // Available (=UP) devices
+    private final Set<DeviceId> availableDevices = Sets.newConcurrentHashSet();
+
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        deviceDescs.clear();
+        devices.clear();
+        devicePorts.clear();
+        availableDevices.clear();
+        log.info("Stopped");
+    }
+
+    @Override
+    public int getDeviceCount() {
+        return devices.size();
+    }
+
+    @Override
+    public Iterable<Device> getDevices() {
+        return Collections.unmodifiableCollection(devices.values());
+    }
+
+    @Override
+    public Iterable<Device> getAvailableDevices() {
+        return FluentIterable.from(getDevices())
+                .filter(new Predicate<Device>() {
+
+                    @Override
+                    public boolean apply(Device input) {
+                        return isAvailable(input.id());
+                    }
+                });
+    }
+
+    @Override
+    public Device getDevice(DeviceId deviceId) {
+        return devices.get(deviceId);
+    }
+
+    @Override
+    public DeviceEvent createOrUpdateDevice(ProviderId providerId,
+                                            DeviceId deviceId,
+                                            DeviceDescription deviceDescription) {
+        Map<ProviderId, DeviceDescriptions> providerDescs
+                = getOrCreateDeviceDescriptions(deviceId);
+
+        synchronized (providerDescs) {
+            // locking per device
+            DeviceDescriptions descs
+                    = getOrCreateProviderDeviceDescriptions(providerDescs,
+                                                            providerId,
+                                                            deviceDescription);
+
+            Device oldDevice = devices.get(deviceId);
+            // update description
+            descs.putDeviceDesc(deviceDescription);
+            Device newDevice = composeDevice(deviceId, providerDescs);
+
+            if (oldDevice == null) {
+                // ADD
+                return createDevice(providerId, newDevice);
+            } else {
+                // UPDATE or ignore (no change or stale)
+                return updateDevice(providerId, oldDevice, newDevice);
+            }
+        }
+    }
+
+    // Creates the device and returns the appropriate event if necessary.
+    // Guarded by deviceDescs value (=Device lock)
+    private DeviceEvent createDevice(ProviderId providerId, Device newDevice) {
+        // update composed device cache
+        Device oldDevice = devices.putIfAbsent(newDevice.id(), newDevice);
+        verify(oldDevice == null,
+               "Unexpected Device in cache. PID:%s [old=%s, new=%s]",
+               providerId, oldDevice, newDevice);
+
+        if (!providerId.isAncillary()) {
+            availableDevices.add(newDevice.id());
+        }
+
+        return new DeviceEvent(DeviceEvent.Type.DEVICE_ADDED, newDevice, null);
+    }
+
+    // Updates the device and returns the appropriate event if necessary.
+    // Guarded by deviceDescs value (=Device lock)
+    private DeviceEvent updateDevice(ProviderId providerId, Device oldDevice, Device newDevice) {
+        // We allow only certain attributes to trigger update
+        boolean propertiesChanged =
+                !Objects.equals(oldDevice.hwVersion(), newDevice.hwVersion()) ||
+                        !Objects.equals(oldDevice.swVersion(), newDevice.swVersion());
+        boolean annotationsChanged =
+                !AnnotationsUtil.isEqual(oldDevice.annotations(), newDevice.annotations());
+
+        // Primary providers can respond to all changes, but ancillary ones
+        // should respond only to annotation changes.
+        if ((providerId.isAncillary() && annotationsChanged) ||
+                (!providerId.isAncillary() && (propertiesChanged || annotationsChanged))) {
+
+            boolean replaced = devices.replace(newDevice.id(), oldDevice, newDevice);
+            if (!replaced) {
+                // FIXME: Is the enclosing if required here?
+                verify(replaced,
+                       "Replacing devices cache failed. PID:%s [expected:%s, found:%s, new=%s]",
+                       providerId, oldDevice, devices.get(newDevice.id())
+                        , newDevice);
+            }
+            if (!providerId.isAncillary()) {
+                availableDevices.add(newDevice.id());
+            }
+            return new DeviceEvent(DeviceEvent.Type.DEVICE_UPDATED, newDevice, null);
+        }
+
+        // Otherwise merely attempt to change availability if primary provider
+        if (!providerId.isAncillary()) {
+            boolean added = availableDevices.add(newDevice.id());
+            return !added ? null :
+                    new DeviceEvent(DEVICE_AVAILABILITY_CHANGED, newDevice, null);
+        }
+        return null;
+    }
+
+    @Override
+    public DeviceEvent markOffline(DeviceId deviceId) {
+        Map<ProviderId, DeviceDescriptions> providerDescs
+                = getOrCreateDeviceDescriptions(deviceId);
+
+        // locking device
+        synchronized (providerDescs) {
+            Device device = devices.get(deviceId);
+            if (device == null) {
+                return null;
+            }
+            boolean removed = availableDevices.remove(deviceId);
+            if (removed) {
+                // TODO: broadcast ... DOWN only?
+                return new DeviceEvent(DEVICE_AVAILABILITY_CHANGED, device, null);
+            }
+            return null;
+        }
+    }
+
+    @Override
+    public List<DeviceEvent> updatePorts(ProviderId providerId,
+                                         DeviceId deviceId,
+                                         List<PortDescription> portDescriptions) {
+        Device device = devices.get(deviceId);
+        if (device == null) {
+            log.debug("Device {} doesn't exist or hasn't been initialized yet", deviceId);
+            return Collections.emptyList();
+        }
+
+        Map<ProviderId, DeviceDescriptions> descsMap = deviceDescs.get(deviceId);
+        checkArgument(descsMap != null, DEVICE_NOT_FOUND, deviceId);
+
+        List<DeviceEvent> events = new ArrayList<>();
+        synchronized (descsMap) {
+            DeviceDescriptions descs = descsMap.get(providerId);
+            // every provider must provide DeviceDescription.
+            checkArgument(descs != null,
+                          "Device description for Device ID %s from Provider %s was not found",
+                          deviceId, providerId);
+
+            Map<PortNumber, Port> ports = getPortMap(deviceId);
+
+            // Add new ports
+            Set<PortNumber> processed = new HashSet<>();
+            for (PortDescription portDescription : portDescriptions) {
+                final PortNumber number = portDescription.portNumber();
+                processed.add(portDescription.portNumber());
+
+                final Port oldPort = ports.get(number);
+                final Port newPort;
+
+// event suppression hook?
+
+                // update description
+                descs.putPortDesc(portDescription);
+                newPort = composePort(device, number, descsMap);
+
+                events.add(oldPort == null ?
+                                   createPort(device, newPort, ports) :
+                                   updatePort(device, oldPort, newPort, ports));
+            }
+
+            events.addAll(pruneOldPorts(device, ports, processed));
+        }
+        return FluentIterable.from(events).filter(notNull()).toList();
+    }
+
+    // Creates a new port based on the port description adds it to the map and
+    // Returns corresponding event.
+    // Guarded by deviceDescs value (=Device lock)
+    private DeviceEvent createPort(Device device, Port newPort,
+                                   Map<PortNumber, Port> ports) {
+        ports.put(newPort.number(), newPort);
+        return new DeviceEvent(PORT_ADDED, device, newPort);
+    }
+
+    // Checks if the specified port requires update and if so, it replaces the
+    // existing entry in the map and returns corresponding event.
+    // Guarded by deviceDescs value (=Device lock)
+    private DeviceEvent updatePort(Device device, Port oldPort,
+                                   Port newPort,
+                                   Map<PortNumber, Port> ports) {
+        if (oldPort.isEnabled() != newPort.isEnabled() ||
+                oldPort.type() != newPort.type() ||
+                oldPort.portSpeed() != newPort.portSpeed() ||
+                !AnnotationsUtil.isEqual(oldPort.annotations(), newPort.annotations())) {
+            ports.put(oldPort.number(), newPort);
+            return new DeviceEvent(PORT_UPDATED, device, newPort);
+        }
+        return null;
+    }
+
+    // Prunes the specified list of ports based on which ports are in the
+    // processed list and returns list of corresponding events.
+    // Guarded by deviceDescs value (=Device lock)
+    private List<DeviceEvent> pruneOldPorts(Device device,
+                                            Map<PortNumber, Port> ports,
+                                            Set<PortNumber> processed) {
+        List<DeviceEvent> events = new ArrayList<>();
+        Iterator<Entry<PortNumber, Port>> iterator = ports.entrySet().iterator();
+        while (iterator.hasNext()) {
+            Entry<PortNumber, Port> e = iterator.next();
+            PortNumber portNumber = e.getKey();
+            if (!processed.contains(portNumber)) {
+                events.add(new DeviceEvent(PORT_REMOVED, device, e.getValue()));
+                iterator.remove();
+            }
+        }
+        return events;
+    }
+
+    // Gets the map of ports for the specified device; if one does not already
+    // exist, it creates and registers a new one.
+    private ConcurrentMap<PortNumber, Port> getPortMap(DeviceId deviceId) {
+        return createIfAbsentUnchecked(devicePorts, deviceId,
+                                       NewConcurrentHashMap.<PortNumber, Port>ifNeeded());
+    }
+
+    private Map<ProviderId, DeviceDescriptions> getOrCreateDeviceDescriptions(
+            DeviceId deviceId) {
+        Map<ProviderId, DeviceDescriptions> r;
+        r = deviceDescs.get(deviceId);
+        if (r != null) {
+            return r;
+        }
+        r = new HashMap<>();
+        final Map<ProviderId, DeviceDescriptions> concurrentlyAdded;
+        concurrentlyAdded = deviceDescs.putIfAbsent(deviceId, r);
+        if (concurrentlyAdded != null) {
+            return concurrentlyAdded;
+        } else {
+            return r;
+        }
+    }
+
+    // Guarded by deviceDescs value (=Device lock)
+    private DeviceDescriptions getOrCreateProviderDeviceDescriptions(
+            Map<ProviderId, DeviceDescriptions> device,
+            ProviderId providerId, DeviceDescription deltaDesc) {
+        synchronized (device) {
+            DeviceDescriptions r = device.get(providerId);
+            if (r == null) {
+                r = new DeviceDescriptions(deltaDesc);
+                device.put(providerId, r);
+            }
+            return r;
+        }
+    }
+
+    @Override
+    public DeviceEvent updatePortStatus(ProviderId providerId, DeviceId deviceId,
+                                        PortDescription portDescription) {
+        Device device = devices.get(deviceId);
+        checkArgument(device != null, DEVICE_NOT_FOUND, deviceId);
+
+        Map<ProviderId, DeviceDescriptions> descsMap = deviceDescs.get(deviceId);
+        checkArgument(descsMap != null, DEVICE_NOT_FOUND, deviceId);
+
+        synchronized (descsMap) {
+            DeviceDescriptions descs = descsMap.get(providerId);
+            // assuming all providers must give DeviceDescription first
+            checkArgument(descs != null,
+                          "Device description for Device ID %s from Provider %s was not found",
+                          deviceId, providerId);
+
+            ConcurrentMap<PortNumber, Port> ports = getPortMap(deviceId);
+            final PortNumber number = portDescription.portNumber();
+            final Port oldPort = ports.get(number);
+            final Port newPort;
+
+            // update description
+            descs.putPortDesc(portDescription);
+            newPort = composePort(device, number, descsMap);
+
+            if (oldPort == null) {
+                return createPort(device, newPort, ports);
+            } else {
+                return updatePort(device, oldPort, newPort, ports);
+            }
+        }
+    }
+
+    @Override
+    public List<Port> getPorts(DeviceId deviceId) {
+        Map<PortNumber, Port> ports = devicePorts.get(deviceId);
+        if (ports == null) {
+            return Collections.emptyList();
+        }
+        return ImmutableList.copyOf(ports.values());
+    }
+
+    @Override
+    public DeviceEvent updatePortStatistics(ProviderId providerId, DeviceId deviceId,
+                                            Collection<PortStatistics> portStats) {
+
+        ConcurrentMap<PortNumber, PortStatistics> statsMap = devicePortStats.get(deviceId);
+        if (statsMap == null) {
+            statsMap = Maps.newConcurrentMap();
+            devicePortStats.put(deviceId, statsMap);
+        }
+
+        for (PortStatistics stat: portStats) {
+            PortNumber portNumber = PortNumber.portNumber(stat.port());
+            statsMap.put(portNumber, stat);
+        }
+
+        return new DeviceEvent(PORT_STATS_UPDATED,  devices.get(deviceId), null);
+    }
+
+    @Override
+    public Port getPort(DeviceId deviceId, PortNumber portNumber) {
+        Map<PortNumber, Port> ports = devicePorts.get(deviceId);
+        return ports == null ? null : ports.get(portNumber);
+    }
+
+    @Override
+    public List<PortStatistics> getPortStatistics(DeviceId deviceId) {
+        Map<PortNumber, PortStatistics> portStats = devicePortStats.get(deviceId);
+        if (portStats == null) {
+            return Collections.emptyList();
+        }
+        return ImmutableList.copyOf(portStats.values());
+    }
+
+    @Override
+    public boolean isAvailable(DeviceId deviceId) {
+        return availableDevices.contains(deviceId);
+    }
+
+    @Override
+    public DeviceEvent removeDevice(DeviceId deviceId) {
+        Map<ProviderId, DeviceDescriptions> descs = getOrCreateDeviceDescriptions(deviceId);
+        synchronized (descs) {
+            Device device = devices.remove(deviceId);
+            // should DEVICE_REMOVED carry removed ports?
+            Map<PortNumber, Port> ports = devicePorts.get(deviceId);
+            if (ports != null) {
+                ports.clear();
+            }
+            availableDevices.remove(deviceId);
+            descs.clear();
+            return device == null ? null :
+                    new DeviceEvent(DEVICE_REMOVED, device, null);
+        }
+    }
+
+    /**
+     * Returns a Device, merging description given from multiple Providers.
+     *
+     * @param deviceId      device identifier
+     * @param providerDescs Collection of Descriptions from multiple providers
+     * @return Device instance
+     */
+    private Device composeDevice(DeviceId deviceId,
+                                 Map<ProviderId, DeviceDescriptions> providerDescs) {
+
+        checkArgument(!providerDescs.isEmpty(), "No Device descriptions supplied");
+
+        ProviderId primary = pickPrimaryPID(providerDescs);
+
+        DeviceDescriptions desc = providerDescs.get(primary);
+
+        final DeviceDescription base = desc.getDeviceDesc();
+        Type type = base.type();
+        String manufacturer = base.manufacturer();
+        String hwVersion = base.hwVersion();
+        String swVersion = base.swVersion();
+        String serialNumber = base.serialNumber();
+        ChassisId chassisId = base.chassisId();
+        DefaultAnnotations annotations = DefaultAnnotations.builder().build();
+        annotations = merge(annotations, base.annotations());
+
+        for (Entry<ProviderId, DeviceDescriptions> e : providerDescs.entrySet()) {
+            if (e.getKey().equals(primary)) {
+                continue;
+            }
+            // TODO: should keep track of Description timestamp
+            // and only merge conflicting keys when timestamp is newer
+            // Currently assuming there will never be a key conflict between
+            // providers
+
+            // annotation merging. not so efficient, should revisit later
+            annotations = merge(annotations, e.getValue().getDeviceDesc().annotations());
+        }
+
+        return new DefaultDevice(primary, deviceId, type, manufacturer,
+                                 hwVersion, swVersion, serialNumber,
+                                 chassisId, annotations);
+    }
+
+    /**
+     * Returns a Port, merging description given from multiple Providers.
+     *
+     * @param device   device the port is on
+     * @param number   port number
+     * @param descsMap Collection of Descriptions from multiple providers
+     * @return Port instance
+     */
+    private Port composePort(Device device, PortNumber number,
+                             Map<ProviderId, DeviceDescriptions> descsMap) {
+
+        ProviderId primary = pickPrimaryPID(descsMap);
+        DeviceDescriptions primDescs = descsMap.get(primary);
+        // if no primary, assume not enabled
+        // TODO: revisit this default port enabled/disabled behavior
+        boolean isEnabled = false;
+        DefaultAnnotations annotations = DefaultAnnotations.builder().build();
+
+        final PortDescription portDesc = primDescs.getPortDesc(number);
+        if (portDesc != null) {
+            isEnabled = portDesc.isEnabled();
+            annotations = merge(annotations, portDesc.annotations());
+        }
+
+        for (Entry<ProviderId, DeviceDescriptions> e : descsMap.entrySet()) {
+            if (e.getKey().equals(primary)) {
+                continue;
+            }
+            // TODO: should keep track of Description timestamp
+            // and only merge conflicting keys when timestamp is newer
+            // Currently assuming there will never be a key conflict between
+            // providers
+
+            // annotation merging. not so efficient, should revisit later
+            final PortDescription otherPortDesc = e.getValue().getPortDesc(number);
+            if (otherPortDesc != null) {
+                annotations = merge(annotations, otherPortDesc.annotations());
+            }
+        }
+
+        return portDesc == null ?
+                new DefaultPort(device, number, false, annotations) :
+                new DefaultPort(device, number, isEnabled, portDesc.type(),
+                                portDesc.portSpeed(), annotations);
+    }
+
+    /**
+     * @return primary ProviderID, or randomly chosen one if none exists
+     */
+    private ProviderId pickPrimaryPID(Map<ProviderId, DeviceDescriptions> descsMap) {
+        ProviderId fallBackPrimary = null;
+        for (Entry<ProviderId, DeviceDescriptions> e : descsMap.entrySet()) {
+            if (!e.getKey().isAncillary()) {
+                return e.getKey();
+            } else if (fallBackPrimary == null) {
+                // pick randomly as a fallback in case there is no primary
+                fallBackPrimary = e.getKey();
+            }
+        }
+        return fallBackPrimary;
+    }
+
+    /**
+     * Collection of Description of a Device and it's Ports given from a Provider.
+     */
+    private static class DeviceDescriptions {
+
+        private final AtomicReference<DeviceDescription> deviceDesc;
+        private final ConcurrentMap<PortNumber, PortDescription> portDescs;
+
+        public DeviceDescriptions(DeviceDescription desc) {
+            this.deviceDesc = new AtomicReference<>(checkNotNull(desc));
+            this.portDescs = new ConcurrentHashMap<>();
+        }
+
+        public DeviceDescription getDeviceDesc() {
+            return deviceDesc.get();
+        }
+
+        public PortDescription getPortDesc(PortNumber number) {
+            return portDescs.get(number);
+        }
+
+        /**
+         * Puts DeviceDescription, merging annotations as necessary.
+         *
+         * @param newDesc new DeviceDescription
+         * @return previous DeviceDescription
+         */
+        public synchronized DeviceDescription putDeviceDesc(DeviceDescription newDesc) {
+            DeviceDescription oldOne = deviceDesc.get();
+            DeviceDescription newOne = newDesc;
+            if (oldOne != null) {
+                SparseAnnotations merged = union(oldOne.annotations(),
+                                                 newDesc.annotations());
+                newOne = new DefaultDeviceDescription(newOne, merged);
+            }
+            return deviceDesc.getAndSet(newOne);
+        }
+
+        /**
+         * Puts PortDescription, merging annotations as necessary.
+         *
+         * @param newDesc new PortDescription
+         * @return previous PortDescription
+         */
+        public synchronized PortDescription putPortDesc(PortDescription newDesc) {
+            PortDescription oldOne = portDescs.get(newDesc.portNumber());
+            PortDescription newOne = newDesc;
+            if (oldOne != null) {
+                SparseAnnotations merged = union(oldOne.annotations(),
+                                                 newDesc.annotations());
+                newOne = new DefaultPortDescription(newOne, merged);
+            }
+            return portDescs.put(newOne.portNumber(), newOne);
+        }
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStoreTest.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStoreTest.java
new file mode 100644
index 0000000..562e6f3
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStoreTest.java
@@ -0,0 +1,530 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ *
+ */
+package org.onosproject.store.trivial;
+
+import static org.junit.Assert.*;
+import static org.onosproject.net.Device.Type.SWITCH;
+import static org.onosproject.net.DeviceId.deviceId;
+import static org.onosproject.net.device.DeviceEvent.Type.*;
+import static org.onosproject.net.NetTestTools.assertAnnotationsEquals;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.onosproject.net.DefaultAnnotations;
+import org.onosproject.net.Device;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Port;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.SparseAnnotations;
+import org.onosproject.net.device.DefaultDeviceDescription;
+import org.onosproject.net.device.DefaultPortDescription;
+import org.onosproject.net.device.DeviceDescription;
+import org.onosproject.net.device.DeviceEvent;
+import org.onosproject.net.device.DeviceStore;
+import org.onosproject.net.device.DeviceStoreDelegate;
+import org.onosproject.net.device.PortDescription;
+import org.onosproject.net.provider.ProviderId;
+
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Sets;
+
+import org.onlab.packet.ChassisId;
+
+/**
+ * Test of the simple DeviceStore implementation.
+ */
+public class SimpleDeviceStoreTest {
+
+    private static final ProviderId PID = new ProviderId("of", "foo");
+    private static final ProviderId PIDA = new ProviderId("of", "bar", true);
+    private static final DeviceId DID1 = deviceId("of:foo");
+    private static final DeviceId DID2 = deviceId("of:bar");
+    private static final String MFR = "whitebox";
+    private static final String HW = "1.1.x";
+    private static final String SW1 = "3.8.1";
+    private static final String SW2 = "3.9.5";
+    private static final String SN = "43311-12345";
+    private static final ChassisId CID = new ChassisId();
+
+    private static final PortNumber P1 = PortNumber.portNumber(1);
+    private static final PortNumber P2 = PortNumber.portNumber(2);
+    private static final PortNumber P3 = PortNumber.portNumber(3);
+
+    private static final SparseAnnotations A1 = DefaultAnnotations.builder()
+            .set("A1", "a1")
+            .set("B1", "b1")
+            .build();
+    private static final SparseAnnotations A1_2 = DefaultAnnotations.builder()
+            .remove("A1")
+            .set("B3", "b3")
+            .build();
+    private static final SparseAnnotations A2 = DefaultAnnotations.builder()
+            .set("A2", "a2")
+            .set("B2", "b2")
+            .build();
+    private static final SparseAnnotations A2_2 = DefaultAnnotations.builder()
+            .remove("A2")
+            .set("B4", "b4")
+            .build();
+
+    private SimpleDeviceStore simpleDeviceStore;
+    private DeviceStore deviceStore;
+
+
+
+    @BeforeClass
+    public static void setUpBeforeClass() throws Exception {
+    }
+
+    @AfterClass
+    public static void tearDownAfterClass() throws Exception {
+    }
+
+
+    @Before
+    public void setUp() throws Exception {
+        simpleDeviceStore = new SimpleDeviceStore();
+        simpleDeviceStore.activate();
+        deviceStore = simpleDeviceStore;
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        simpleDeviceStore.deactivate();
+    }
+
+    private void putDevice(DeviceId deviceId, String swVersion,
+                           SparseAnnotations... annotations) {
+        DeviceDescription description =
+                new DefaultDeviceDescription(deviceId.uri(), SWITCH, MFR,
+                        HW, swVersion, SN, CID, annotations);
+        deviceStore.createOrUpdateDevice(PID, deviceId, description);
+    }
+
+    private void putDeviceAncillary(DeviceId deviceId, String swVersion,
+                                    SparseAnnotations... annotations) {
+        DeviceDescription description =
+                new DefaultDeviceDescription(deviceId.uri(), SWITCH, MFR,
+                        HW, swVersion, SN, CID, annotations);
+        deviceStore.createOrUpdateDevice(PIDA, deviceId, description);
+    }
+
+    private static void assertDevice(DeviceId id, String swVersion, Device device) {
+        assertNotNull(device);
+        assertEquals(id, device.id());
+        assertEquals(MFR, device.manufacturer());
+        assertEquals(HW, device.hwVersion());
+        assertEquals(swVersion, device.swVersion());
+        assertEquals(SN, device.serialNumber());
+    }
+
+    @Test
+    public final void testGetDeviceCount() {
+        assertEquals("initialy empty", 0, deviceStore.getDeviceCount());
+
+        putDevice(DID1, SW1);
+        putDevice(DID2, SW2);
+        putDevice(DID1, SW1);
+
+        assertEquals("expect 2 uniq devices", 2, deviceStore.getDeviceCount());
+    }
+
+    @Test
+    public final void testGetDevices() {
+        assertEquals("initialy empty", 0, Iterables.size(deviceStore.getDevices()));
+
+        putDevice(DID1, SW1);
+        putDevice(DID2, SW2);
+        putDevice(DID1, SW1);
+
+        assertEquals("expect 2 uniq devices",
+                2, Iterables.size(deviceStore.getDevices()));
+
+        Map<DeviceId, Device> devices = new HashMap<>();
+        for (Device device : deviceStore.getDevices()) {
+            devices.put(device.id(), device);
+        }
+
+        assertDevice(DID1, SW1, devices.get(DID1));
+        assertDevice(DID2, SW2, devices.get(DID2));
+
+        // add case for new node?
+    }
+
+    @Test
+    public final void testGetDevice() {
+
+        putDevice(DID1, SW1);
+
+        assertDevice(DID1, SW1, deviceStore.getDevice(DID1));
+        assertNull("DID2 shouldn't be there", deviceStore.getDevice(DID2));
+    }
+
+    @Test
+    public final void testCreateOrUpdateDevice() {
+        DeviceDescription description =
+                new DefaultDeviceDescription(DID1.uri(), SWITCH, MFR,
+                        HW, SW1, SN, CID);
+        DeviceEvent event = deviceStore.createOrUpdateDevice(PID, DID1, description);
+        assertEquals(DEVICE_ADDED, event.type());
+        assertDevice(DID1, SW1, event.subject());
+
+        DeviceDescription description2 =
+                new DefaultDeviceDescription(DID1.uri(), SWITCH, MFR,
+                        HW, SW2, SN, CID);
+        DeviceEvent event2 = deviceStore.createOrUpdateDevice(PID, DID1, description2);
+        assertEquals(DEVICE_UPDATED, event2.type());
+        assertDevice(DID1, SW2, event2.subject());
+
+        assertNull("No change expected", deviceStore.createOrUpdateDevice(PID, DID1, description2));
+    }
+
+    @Test
+    public final void testCreateOrUpdateDeviceAncillary() {
+        DeviceDescription description =
+                new DefaultDeviceDescription(DID1.uri(), SWITCH, MFR,
+                        HW, SW1, SN, CID, A2);
+        DeviceEvent event = deviceStore.createOrUpdateDevice(PIDA, DID1, description);
+        assertEquals(DEVICE_ADDED, event.type());
+        assertDevice(DID1, SW1, event.subject());
+        assertEquals(PIDA, event.subject().providerId());
+        assertAnnotationsEquals(event.subject().annotations(), A2);
+        assertFalse("Ancillary will not bring device up", deviceStore.isAvailable(DID1));
+
+        DeviceDescription description2 =
+                new DefaultDeviceDescription(DID1.uri(), SWITCH, MFR,
+                        HW, SW2, SN, CID, A1);
+        DeviceEvent event2 = deviceStore.createOrUpdateDevice(PID, DID1, description2);
+        assertEquals(DEVICE_UPDATED, event2.type());
+        assertDevice(DID1, SW2, event2.subject());
+        assertEquals(PID, event2.subject().providerId());
+        assertAnnotationsEquals(event2.subject().annotations(), A1, A2);
+        assertTrue(deviceStore.isAvailable(DID1));
+
+        assertNull("No change expected", deviceStore.createOrUpdateDevice(PID, DID1, description2));
+
+        // For now, Ancillary is ignored once primary appears
+        assertNull("No change expected", deviceStore.createOrUpdateDevice(PIDA, DID1, description));
+
+        // But, Ancillary annotations will be in effect
+        DeviceDescription description3 =
+                new DefaultDeviceDescription(DID1.uri(), SWITCH, MFR,
+                        HW, SW1, SN, CID, A2_2);
+        DeviceEvent event3 = deviceStore.createOrUpdateDevice(PIDA, DID1, description3);
+        assertEquals(DEVICE_UPDATED, event3.type());
+        // basic information will be the one from Primary
+        assertDevice(DID1, SW2, event3.subject());
+        assertEquals(PID, event3.subject().providerId());
+        // but annotation from Ancillary will be merged
+        assertAnnotationsEquals(event3.subject().annotations(), A1, A2, A2_2);
+        assertTrue(deviceStore.isAvailable(DID1));
+    }
+
+
+    @Test
+    public final void testMarkOffline() {
+
+        putDevice(DID1, SW1);
+        assertTrue(deviceStore.isAvailable(DID1));
+
+        DeviceEvent event = deviceStore.markOffline(DID1);
+        assertEquals(DEVICE_AVAILABILITY_CHANGED, event.type());
+        assertDevice(DID1, SW1, event.subject());
+        assertFalse(deviceStore.isAvailable(DID1));
+
+        DeviceEvent event2 = deviceStore.markOffline(DID1);
+        assertNull("No change, no event", event2);
+}
+
+    @Test
+    public final void testUpdatePorts() {
+        putDevice(DID1, SW1);
+        List<PortDescription> pds = Arrays.<PortDescription>asList(
+                new DefaultPortDescription(P1, true),
+                new DefaultPortDescription(P2, true)
+                );
+
+        List<DeviceEvent> events = deviceStore.updatePorts(PID, DID1, pds);
+
+        Set<PortNumber> expectedPorts = Sets.newHashSet(P1, P2);
+        for (DeviceEvent event : events) {
+            assertEquals(PORT_ADDED, event.type());
+            assertDevice(DID1, SW1, event.subject());
+            assertTrue("PortNumber is one of expected",
+                    expectedPorts.remove(event.port().number()));
+            assertTrue("Port is enabled", event.port().isEnabled());
+        }
+        assertTrue("Event for all expectedport appeared", expectedPorts.isEmpty());
+
+
+        List<PortDescription> pds2 = Arrays.<PortDescription>asList(
+                new DefaultPortDescription(P1, false),
+                new DefaultPortDescription(P2, true),
+                new DefaultPortDescription(P3, true)
+                );
+
+        events = deviceStore.updatePorts(PID, DID1, pds2);
+        assertFalse("event should be triggered", events.isEmpty());
+        for (DeviceEvent event : events) {
+            PortNumber num = event.port().number();
+            if (P1.equals(num)) {
+                assertEquals(PORT_UPDATED, event.type());
+                assertDevice(DID1, SW1, event.subject());
+                assertFalse("Port is disabled", event.port().isEnabled());
+            } else if (P2.equals(num)) {
+                fail("P2 event not expected.");
+            } else if (P3.equals(num)) {
+                assertEquals(PORT_ADDED, event.type());
+                assertDevice(DID1, SW1, event.subject());
+                assertTrue("Port is enabled", event.port().isEnabled());
+            } else {
+                fail("Unknown port number encountered: " + num);
+            }
+        }
+
+        List<PortDescription> pds3 = Arrays.<PortDescription>asList(
+                new DefaultPortDescription(P1, false),
+                new DefaultPortDescription(P2, true)
+                );
+        events = deviceStore.updatePorts(PID, DID1, pds3);
+        assertFalse("event should be triggered", events.isEmpty());
+        for (DeviceEvent event : events) {
+            PortNumber num = event.port().number();
+            if (P1.equals(num)) {
+                fail("P1 event not expected.");
+            } else if (P2.equals(num)) {
+                fail("P2 event not expected.");
+            } else if (P3.equals(num)) {
+                assertEquals(PORT_REMOVED, event.type());
+                assertDevice(DID1, SW1, event.subject());
+                assertTrue("Port was enabled", event.port().isEnabled());
+            } else {
+                fail("Unknown port number encountered: " + num);
+            }
+        }
+
+    }
+
+    @Test
+    public final void testUpdatePortStatus() {
+        putDevice(DID1, SW1);
+        List<PortDescription> pds = Arrays.<PortDescription>asList(
+                new DefaultPortDescription(P1, true)
+                );
+        deviceStore.updatePorts(PID, DID1, pds);
+
+        DeviceEvent event = deviceStore.updatePortStatus(PID, DID1,
+                new DefaultPortDescription(P1, false));
+        assertEquals(PORT_UPDATED, event.type());
+        assertDevice(DID1, SW1, event.subject());
+        assertEquals(P1, event.port().number());
+        assertFalse("Port is disabled", event.port().isEnabled());
+
+    }
+
+    @Test
+    public final void testUpdatePortStatusAncillary() {
+        putDeviceAncillary(DID1, SW1);
+        putDevice(DID1, SW1);
+        List<PortDescription> pds = Arrays.<PortDescription>asList(
+                new DefaultPortDescription(P1, true, A1)
+                );
+        deviceStore.updatePorts(PID, DID1, pds);
+
+        DeviceEvent event = deviceStore.updatePortStatus(PID, DID1,
+                new DefaultPortDescription(P1, false, A1_2));
+        assertEquals(PORT_UPDATED, event.type());
+        assertDevice(DID1, SW1, event.subject());
+        assertEquals(P1, event.port().number());
+        assertAnnotationsEquals(event.port().annotations(), A1, A1_2);
+        assertFalse("Port is disabled", event.port().isEnabled());
+
+        DeviceEvent event2 = deviceStore.updatePortStatus(PIDA, DID1,
+                new DefaultPortDescription(P1, true));
+        assertNull("Ancillary is ignored if primary exists", event2);
+
+        // but, Ancillary annotation update will be notified
+        DeviceEvent event3 = deviceStore.updatePortStatus(PIDA, DID1,
+                new DefaultPortDescription(P1, true, A2));
+        assertEquals(PORT_UPDATED, event3.type());
+        assertDevice(DID1, SW1, event3.subject());
+        assertEquals(P1, event3.port().number());
+        assertAnnotationsEquals(event3.port().annotations(), A1, A1_2, A2);
+        assertFalse("Port is disabled", event3.port().isEnabled());
+
+        // port only reported from Ancillary will be notified as down
+        DeviceEvent event4 = deviceStore.updatePortStatus(PIDA, DID1,
+                new DefaultPortDescription(P2, true));
+        assertEquals(PORT_ADDED, event4.type());
+        assertDevice(DID1, SW1, event4.subject());
+        assertEquals(P2, event4.port().number());
+        assertAnnotationsEquals(event4.port().annotations());
+        assertFalse("Port is disabled if not given from primary provider",
+                        event4.port().isEnabled());
+    }
+
+    @Test
+    public final void testGetPorts() {
+        putDevice(DID1, SW1);
+        putDevice(DID2, SW1);
+        List<PortDescription> pds = Arrays.<PortDescription>asList(
+                new DefaultPortDescription(P1, true),
+                new DefaultPortDescription(P2, true)
+                );
+        deviceStore.updatePorts(PID, DID1, pds);
+
+        Set<PortNumber> expectedPorts = Sets.newHashSet(P1, P2);
+        List<Port> ports = deviceStore.getPorts(DID1);
+        for (Port port : ports) {
+            assertTrue("Port is enabled", port.isEnabled());
+            assertTrue("PortNumber is one of expected",
+                    expectedPorts.remove(port.number()));
+        }
+        assertTrue("Event for all expectedport appeared", expectedPorts.isEmpty());
+
+
+        assertTrue("DID2 has no ports", deviceStore.getPorts(DID2).isEmpty());
+    }
+
+    @Test
+    public final void testGetPort() {
+        putDevice(DID1, SW1);
+        putDevice(DID2, SW1);
+        List<PortDescription> pds = Arrays.<PortDescription>asList(
+                new DefaultPortDescription(P1, true),
+                new DefaultPortDescription(P2, false)
+                );
+        deviceStore.updatePorts(PID, DID1, pds);
+
+        Port port1 = deviceStore.getPort(DID1, P1);
+        assertEquals(P1, port1.number());
+        assertTrue("Port is enabled", port1.isEnabled());
+
+        Port port2 = deviceStore.getPort(DID1, P2);
+        assertEquals(P2, port2.number());
+        assertFalse("Port is disabled", port2.isEnabled());
+
+        Port port3 = deviceStore.getPort(DID1, P3);
+        assertNull("P3 not expected", port3);
+    }
+
+    @Test
+    public final void testRemoveDevice() {
+        putDevice(DID1, SW1, A1);
+        List<PortDescription> pds = Arrays.<PortDescription>asList(
+                new DefaultPortDescription(P1, true, A2)
+                );
+        deviceStore.updatePorts(PID, DID1, pds);
+        putDevice(DID2, SW1);
+
+        assertEquals(2, deviceStore.getDeviceCount());
+        assertEquals(1, deviceStore.getPorts(DID1).size());
+        assertAnnotationsEquals(deviceStore.getDevice(DID1).annotations(), A1);
+        assertAnnotationsEquals(deviceStore.getPort(DID1, P1).annotations(), A2);
+
+        DeviceEvent event = deviceStore.removeDevice(DID1);
+        assertEquals(DEVICE_REMOVED, event.type());
+        assertDevice(DID1, SW1, event.subject());
+
+        assertEquals(1, deviceStore.getDeviceCount());
+        assertEquals(0, deviceStore.getPorts(DID1).size());
+
+        // putBack Device, Port w/o annotation
+        putDevice(DID1, SW1);
+        List<PortDescription> pds2 = Arrays.<PortDescription>asList(
+                new DefaultPortDescription(P1, true)
+                );
+        deviceStore.updatePorts(PID, DID1, pds2);
+
+        // annotations should not survive
+        assertEquals(2, deviceStore.getDeviceCount());
+        assertEquals(1, deviceStore.getPorts(DID1).size());
+        assertAnnotationsEquals(deviceStore.getDevice(DID1).annotations());
+        assertAnnotationsEquals(deviceStore.getPort(DID1, P1).annotations());
+    }
+
+    // If Delegates should be called only on remote events,
+    // then Simple* should never call them, thus not test required.
+    // TODO add test for Port events when we have them
+    @Ignore("Ignore until Delegate spec. is clear.")
+    @Test
+    public final void testEvents() throws InterruptedException {
+        final CountDownLatch addLatch = new CountDownLatch(1);
+        DeviceStoreDelegate checkAdd = new DeviceStoreDelegate() {
+            @Override
+            public void notify(DeviceEvent event) {
+                assertEquals(DEVICE_ADDED, event.type());
+                assertDevice(DID1, SW1, event.subject());
+                addLatch.countDown();
+            }
+        };
+        final CountDownLatch updateLatch = new CountDownLatch(1);
+        DeviceStoreDelegate checkUpdate = new DeviceStoreDelegate() {
+            @Override
+            public void notify(DeviceEvent event) {
+                assertEquals(DEVICE_UPDATED, event.type());
+                assertDevice(DID1, SW2, event.subject());
+                updateLatch.countDown();
+            }
+        };
+        final CountDownLatch removeLatch = new CountDownLatch(1);
+        DeviceStoreDelegate checkRemove = new DeviceStoreDelegate() {
+            @Override
+            public void notify(DeviceEvent event) {
+                assertEquals(DEVICE_REMOVED, event.type());
+                assertDevice(DID1, SW2, event.subject());
+                removeLatch.countDown();
+            }
+        };
+
+        DeviceDescription description =
+                new DefaultDeviceDescription(DID1.uri(), SWITCH, MFR,
+                        HW, SW1, SN, CID);
+        deviceStore.setDelegate(checkAdd);
+        deviceStore.createOrUpdateDevice(PID, DID1, description);
+        assertTrue("Add event fired", addLatch.await(1, TimeUnit.SECONDS));
+
+
+        DeviceDescription description2 =
+                new DefaultDeviceDescription(DID1.uri(), SWITCH, MFR,
+                        HW, SW2, SN, CID);
+        deviceStore.unsetDelegate(checkAdd);
+        deviceStore.setDelegate(checkUpdate);
+        deviceStore.createOrUpdateDevice(PID, DID1, description2);
+        assertTrue("Update event fired", updateLatch.await(1, TimeUnit.SECONDS));
+
+        deviceStore.unsetDelegate(checkUpdate);
+        deviceStore.setDelegate(checkRemove);
+        deviceStore.removeDevice(DID1);
+        assertTrue("Remove event fired", removeLatch.await(1, TimeUnit.SECONDS));
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleFlowRuleStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleFlowRuleStore.java
new file mode 100644
index 0000000..3b8f1d3
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleFlowRuleStore.java
@@ -0,0 +1,327 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.base.Function;
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.RemovalListener;
+import com.google.common.cache.RemovalNotification;
+import com.google.common.collect.FluentIterable;
+import com.google.common.collect.Sets;
+import com.google.common.util.concurrent.SettableFuture;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.util.NewConcurrentHashMap;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.flow.CompletedBatchOperation;
+import org.onosproject.net.flow.DefaultFlowEntry;
+import org.onosproject.net.flow.FlowEntry;
+import org.onosproject.net.flow.FlowEntry.FlowEntryState;
+import org.onosproject.net.flow.FlowId;
+import org.onosproject.net.flow.FlowRule;
+import org.onosproject.net.flow.FlowRuleBatchEntry;
+import org.onosproject.net.flow.FlowRuleBatchEntry.FlowRuleOperation;
+import org.onosproject.net.flow.FlowRuleBatchEvent;
+import org.onosproject.net.flow.FlowRuleBatchOperation;
+import org.onosproject.net.flow.FlowRuleBatchRequest;
+import org.onosproject.net.flow.FlowRuleEvent;
+import org.onosproject.net.flow.FlowRuleEvent.Type;
+import org.onosproject.net.flow.FlowRuleStore;
+import org.onosproject.net.flow.FlowRuleStoreDelegate;
+import org.onosproject.net.flow.StoredFlowEntry;
+import org.onosproject.store.AbstractStore;
+import org.slf4j.Logger;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.apache.commons.lang3.concurrent.ConcurrentUtils.createIfAbsentUnchecked;
+import static org.onosproject.net.flow.FlowRuleEvent.Type.RULE_REMOVED;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Manages inventory of flow rules using trivial in-memory implementation.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleFlowRuleStore
+        extends AbstractStore<FlowRuleBatchEvent, FlowRuleStoreDelegate>
+        implements FlowRuleStore {
+
+    private final Logger log = getLogger(getClass());
+
+
+    // inner Map is Device flow table
+    // inner Map value (FlowId synonym list) must be synchronized before modifying
+    private final ConcurrentMap<DeviceId, ConcurrentMap<FlowId, List<StoredFlowEntry>>>
+            flowEntries = new ConcurrentHashMap<>();
+
+    private final AtomicInteger localBatchIdGen = new AtomicInteger();
+
+    // TODO: make this configurable
+    private int pendingFutureTimeoutMinutes = 5;
+
+    private Cache<Integer, SettableFuture<CompletedBatchOperation>> pendingFutures =
+            CacheBuilder.newBuilder()
+                .expireAfterWrite(pendingFutureTimeoutMinutes, TimeUnit.MINUTES)
+                .removalListener(new TimeoutFuture())
+                .build();
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        flowEntries.clear();
+        log.info("Stopped");
+    }
+
+
+    @Override
+    public int getFlowRuleCount() {
+        int sum = 0;
+        for (ConcurrentMap<FlowId, List<StoredFlowEntry>> ft : flowEntries.values()) {
+            for (List<StoredFlowEntry> fes : ft.values()) {
+                sum += fes.size();
+            }
+        }
+        return sum;
+    }
+
+    private static NewConcurrentHashMap<FlowId, List<StoredFlowEntry>> lazyEmptyFlowTable() {
+        return NewConcurrentHashMap.<FlowId, List<StoredFlowEntry>>ifNeeded();
+    }
+
+    /**
+     * Returns the flow table for specified device.
+     *
+     * @param deviceId identifier of the device
+     * @return Map representing Flow Table of given device.
+     */
+    private ConcurrentMap<FlowId, List<StoredFlowEntry>> getFlowTable(DeviceId deviceId) {
+        return createIfAbsentUnchecked(flowEntries,
+                                       deviceId, lazyEmptyFlowTable());
+    }
+
+    private List<StoredFlowEntry> getFlowEntries(DeviceId deviceId, FlowId flowId) {
+        final ConcurrentMap<FlowId, List<StoredFlowEntry>> flowTable = getFlowTable(deviceId);
+        List<StoredFlowEntry> r = flowTable.get(flowId);
+        if (r == null) {
+            final List<StoredFlowEntry> concurrentlyAdded;
+            r = new CopyOnWriteArrayList<>();
+            concurrentlyAdded = flowTable.putIfAbsent(flowId, r);
+            if (concurrentlyAdded != null) {
+                return concurrentlyAdded;
+            }
+        }
+        return r;
+    }
+
+    private FlowEntry getFlowEntryInternal(DeviceId deviceId, FlowRule rule) {
+        List<StoredFlowEntry> fes = getFlowEntries(deviceId, rule.id());
+        for (StoredFlowEntry fe : fes) {
+            if (fe.equals(rule)) {
+                return fe;
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public FlowEntry getFlowEntry(FlowRule rule) {
+        return getFlowEntryInternal(rule.deviceId(), rule);
+    }
+
+    @Override
+    public Iterable<FlowEntry> getFlowEntries(DeviceId deviceId) {
+        // flatten and make iterator unmodifiable
+        return FluentIterable.from(getFlowTable(deviceId).values())
+                .transformAndConcat(
+                        new Function<List<StoredFlowEntry>, Iterable<? extends FlowEntry>>() {
+
+                            @Override
+                            public Iterable<? extends FlowEntry> apply(
+                                    List<StoredFlowEntry> input) {
+                                return Collections.unmodifiableList(input);
+                            }
+                        });
+    }
+
+    @Override
+    public void storeFlowRule(FlowRule rule) {
+        storeFlowRuleInternal(rule);
+    }
+
+    private void storeFlowRuleInternal(FlowRule rule) {
+        StoredFlowEntry f = new DefaultFlowEntry(rule);
+        final DeviceId did = f.deviceId();
+        final FlowId fid = f.id();
+        List<StoredFlowEntry> existing = getFlowEntries(did, fid);
+        synchronized (existing) {
+            for (StoredFlowEntry fe : existing) {
+                if (fe.equals(rule)) {
+                    // was already there? ignore
+                    return;
+                }
+            }
+            // new flow rule added
+            existing.add(f);
+        }
+    }
+
+    @Override
+    public void deleteFlowRule(FlowRule rule) {
+
+        List<StoredFlowEntry> entries = getFlowEntries(rule.deviceId(), rule.id());
+
+        synchronized (entries) {
+            for (StoredFlowEntry entry : entries) {
+                if (entry.equals(rule)) {
+                    synchronized (entry) {
+                        entry.setState(FlowEntryState.PENDING_REMOVE);
+                    }
+                }
+            }
+        }
+
+
+        //log.warn("Cannot find rule {}", rule);
+    }
+
+    @Override
+    public FlowRuleEvent addOrUpdateFlowRule(FlowEntry rule) {
+        // check if this new rule is an update to an existing entry
+        List<StoredFlowEntry> entries = getFlowEntries(rule.deviceId(), rule.id());
+        synchronized (entries) {
+            for (StoredFlowEntry stored : entries) {
+                if (stored.equals(rule)) {
+                    synchronized (stored) {
+                        stored.setBytes(rule.bytes());
+                        stored.setLife(rule.life());
+                        stored.setPackets(rule.packets());
+                        if (stored.state() == FlowEntryState.PENDING_ADD) {
+                            stored.setState(FlowEntryState.ADDED);
+                            // TODO: Do we need to change `rule` state?
+                            return new FlowRuleEvent(Type.RULE_ADDED, rule);
+                        }
+                        return new FlowRuleEvent(Type.RULE_UPDATED, rule);
+                    }
+                }
+            }
+        }
+
+        // should not reach here
+        // storeFlowRule was expected to be called
+        log.error("FlowRule was not found in store {} to update", rule);
+
+        //flowEntries.put(did, rule);
+        return null;
+    }
+
+    @Override
+    public FlowRuleEvent removeFlowRule(FlowEntry rule) {
+        // This is where one could mark a rule as removed and still keep it in the store.
+        final DeviceId did = rule.deviceId();
+
+        List<StoredFlowEntry> entries = getFlowEntries(did, rule.id());
+        synchronized (entries) {
+            if (entries.remove(rule)) {
+                return new FlowRuleEvent(RULE_REMOVED, rule);
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public void storeBatch(
+            FlowRuleBatchOperation operation) {
+        List<FlowRuleBatchEntry> toAdd = new ArrayList<>();
+        List<FlowRuleBatchEntry> toRemove = new ArrayList<>();
+
+        for (FlowRuleBatchEntry entry : operation.getOperations()) {
+            final FlowRule flowRule = entry.target();
+            if (entry.operator().equals(FlowRuleOperation.ADD)) {
+                if (!getFlowEntries(flowRule.deviceId(), flowRule.id()).contains(flowRule)) {
+                    storeFlowRule(flowRule);
+                    toAdd.add(entry);
+                }
+            } else if (entry.operator().equals(FlowRuleOperation.REMOVE)) {
+                if (getFlowEntries(flowRule.deviceId(), flowRule.id()).contains(flowRule)) {
+                    deleteFlowRule(flowRule);
+                    toRemove.add(entry);
+                }
+            } else {
+                throw new UnsupportedOperationException("Unsupported operation type");
+            }
+        }
+
+        if (toAdd.isEmpty() && toRemove.isEmpty()) {
+            notifyDelegate(FlowRuleBatchEvent.completed(
+                    new FlowRuleBatchRequest(operation.id(), Collections.emptySet()),
+                    new CompletedBatchOperation(true, Collections.emptySet(),
+                                                operation.deviceId())));
+            return;
+        }
+
+        SettableFuture<CompletedBatchOperation> r = SettableFuture.create();
+        final int batchId = localBatchIdGen.incrementAndGet();
+
+        pendingFutures.put(batchId, r);
+
+        toAdd.addAll(toRemove);
+        notifyDelegate(FlowRuleBatchEvent.requested(
+                new FlowRuleBatchRequest(batchId, Sets.newHashSet(toAdd)), operation.deviceId()));
+
+    }
+
+    @Override
+    public void batchOperationComplete(FlowRuleBatchEvent event) {
+        final Long batchId = event.subject().batchId();
+        SettableFuture<CompletedBatchOperation> future
+            = pendingFutures.getIfPresent(batchId);
+        if (future != null) {
+            future.set(event.result());
+            pendingFutures.invalidate(batchId);
+        }
+        notifyDelegate(event);
+    }
+
+    private static final class TimeoutFuture
+        implements RemovalListener<Integer, SettableFuture<CompletedBatchOperation>> {
+        @Override
+        public void onRemoval(RemovalNotification<Integer, SettableFuture<CompletedBatchOperation>> notification) {
+            // wrapping in ExecutionException to support Future.get
+            if (notification.wasEvicted()) {
+                notification.getValue()
+                    .setException(new ExecutionException("Timed out",
+                                                     new TimeoutException()));
+            }
+        }
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleGroupStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleGroupStore.java
new file mode 100644
index 0000000..71de3e1
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleGroupStore.java
@@ -0,0 +1,717 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import static org.apache.commons.lang3.concurrent.ConcurrentUtils.createIfAbsentUnchecked;
+import static org.slf4j.LoggerFactory.getLogger;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.util.NewConcurrentHashMap;
+import org.onosproject.core.DefaultGroupId;
+import org.onosproject.core.GroupId;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.group.DefaultGroup;
+import org.onosproject.net.group.DefaultGroupDescription;
+import org.onosproject.net.group.Group;
+import org.onosproject.net.group.Group.GroupState;
+import org.onosproject.net.group.GroupBucket;
+import org.onosproject.net.group.GroupBuckets;
+import org.onosproject.net.group.GroupDescription;
+import org.onosproject.net.group.GroupEvent;
+import org.onosproject.net.group.GroupEvent.Type;
+import org.onosproject.net.group.GroupKey;
+import org.onosproject.net.group.GroupOperation;
+import org.onosproject.net.group.GroupStore;
+import org.onosproject.net.group.GroupStoreDelegate;
+import org.onosproject.net.group.StoredGroupBucketEntry;
+import org.onosproject.net.group.StoredGroupEntry;
+import org.onosproject.store.AbstractStore;
+import org.slf4j.Logger;
+
+import com.google.common.base.Function;
+import com.google.common.collect.FluentIterable;
+import com.google.common.collect.Sets;
+
+/**
+ * Manages inventory of group entries using trivial in-memory implementation.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleGroupStore
+        extends AbstractStore<GroupEvent, GroupStoreDelegate>
+        implements GroupStore {
+
+    private final Logger log = getLogger(getClass());
+
+    private final int dummyId = 0xffffffff;
+    private final GroupId dummyGroupId = new DefaultGroupId(dummyId);
+
+    // inner Map is per device group table
+    private final ConcurrentMap<DeviceId, ConcurrentMap<GroupKey, StoredGroupEntry>>
+            groupEntriesByKey = new ConcurrentHashMap<>();
+    private final ConcurrentMap<DeviceId, ConcurrentMap<GroupId, StoredGroupEntry>>
+            groupEntriesById = new ConcurrentHashMap<>();
+    private final ConcurrentMap<DeviceId, ConcurrentMap<GroupKey, StoredGroupEntry>>
+            pendingGroupEntriesByKey = new ConcurrentHashMap<>();
+    private final ConcurrentMap<DeviceId, ConcurrentMap<GroupId, Group>>
+        extraneousGroupEntriesById = new ConcurrentHashMap<>();
+
+    private final HashMap<DeviceId, Boolean> deviceAuditStatus =
+            new HashMap<DeviceId, Boolean>();
+
+    private final AtomicInteger groupIdGen = new AtomicInteger();
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        groupEntriesByKey.clear();
+        groupEntriesById.clear();
+        log.info("Stopped");
+    }
+
+    private static NewConcurrentHashMap<GroupKey, StoredGroupEntry>
+                        lazyEmptyGroupKeyTable() {
+        return NewConcurrentHashMap.<GroupKey, StoredGroupEntry>ifNeeded();
+    }
+
+    private static NewConcurrentHashMap<GroupId, StoredGroupEntry>
+                        lazyEmptyGroupIdTable() {
+        return NewConcurrentHashMap.<GroupId, StoredGroupEntry>ifNeeded();
+    }
+
+    private static NewConcurrentHashMap<GroupKey, StoredGroupEntry>
+                        lazyEmptyPendingGroupKeyTable() {
+        return NewConcurrentHashMap.<GroupKey, StoredGroupEntry>ifNeeded();
+    }
+
+    private static NewConcurrentHashMap<GroupId, Group>
+                        lazyEmptyExtraneousGroupIdTable() {
+        return NewConcurrentHashMap.<GroupId, Group>ifNeeded();
+    }
+
+    /**
+     * Returns the group key table for specified device.
+     *
+     * @param deviceId identifier of the device
+     * @return Map representing group key table of given device.
+     */
+    private ConcurrentMap<GroupKey, StoredGroupEntry> getGroupKeyTable(DeviceId deviceId) {
+        return createIfAbsentUnchecked(groupEntriesByKey,
+                                       deviceId, lazyEmptyGroupKeyTable());
+    }
+
+    /**
+     * Returns the group id table for specified device.
+     *
+     * @param deviceId identifier of the device
+     * @return Map representing group key table of given device.
+     */
+    private ConcurrentMap<GroupId, StoredGroupEntry> getGroupIdTable(DeviceId deviceId) {
+        return createIfAbsentUnchecked(groupEntriesById,
+                                       deviceId, lazyEmptyGroupIdTable());
+    }
+
+    /**
+     * Returns the pending group key table for specified device.
+     *
+     * @param deviceId identifier of the device
+     * @return Map representing group key table of given device.
+     */
+    private ConcurrentMap<GroupKey, StoredGroupEntry>
+                    getPendingGroupKeyTable(DeviceId deviceId) {
+        return createIfAbsentUnchecked(pendingGroupEntriesByKey,
+                                       deviceId, lazyEmptyPendingGroupKeyTable());
+    }
+
+    /**
+     * Returns the extraneous group id table for specified device.
+     *
+     * @param deviceId identifier of the device
+     * @return Map representing group key table of given device.
+     */
+    private ConcurrentMap<GroupId, Group>
+                getExtraneousGroupIdTable(DeviceId deviceId) {
+        return createIfAbsentUnchecked(extraneousGroupEntriesById,
+                                       deviceId,
+                                       lazyEmptyExtraneousGroupIdTable());
+    }
+
+    /**
+     * Returns the number of groups for the specified device in the store.
+     *
+     * @return number of groups for the specified device
+     */
+    @Override
+    public int getGroupCount(DeviceId deviceId) {
+        return (groupEntriesByKey.get(deviceId) != null) ?
+                 groupEntriesByKey.get(deviceId).size() : 0;
+    }
+
+    /**
+     * Returns the groups associated with a device.
+     *
+     * @param deviceId the device ID
+     *
+     * @return the group entries
+     */
+    @Override
+    public Iterable<Group> getGroups(DeviceId deviceId) {
+        // flatten and make iterator unmodifiable
+        return FluentIterable.from(getGroupKeyTable(deviceId).values())
+            .transform(
+                    new Function<StoredGroupEntry, Group>() {
+
+                        @Override
+                        public Group apply(
+                                StoredGroupEntry input) {
+                            return input;
+                        }
+                    });
+    }
+
+    /**
+     * Returns the stored group entry.
+     *
+     * @param deviceId the device ID
+     * @param appCookie the group key
+     *
+     * @return a group associated with the key
+     */
+    @Override
+    public Group getGroup(DeviceId deviceId, GroupKey appCookie) {
+        return (groupEntriesByKey.get(deviceId) != null) ?
+                      groupEntriesByKey.get(deviceId).get(appCookie) :
+                      null;
+    }
+
+    @Override
+    public Group getGroup(DeviceId deviceId, GroupId groupId) {
+        return (groupEntriesById.get(deviceId) != null) ?
+                      groupEntriesById.get(deviceId).get(groupId) :
+                      null;
+    }
+
+    private int getFreeGroupIdValue(DeviceId deviceId) {
+        int freeId = groupIdGen.incrementAndGet();
+
+        while (true) {
+            Group existing = (
+                    groupEntriesById.get(deviceId) != null) ?
+                    groupEntriesById.get(deviceId).get(new DefaultGroupId(freeId)) :
+                    null;
+            if (existing == null) {
+                existing = (
+                        extraneousGroupEntriesById.get(deviceId) != null) ?
+                        extraneousGroupEntriesById.get(deviceId).
+                        get(new DefaultGroupId(freeId)) :
+                        null;
+            }
+            if (existing != null) {
+                freeId = groupIdGen.incrementAndGet();
+            } else {
+                break;
+            }
+        }
+        return freeId;
+    }
+
+    /**
+     * Stores a new group entry using the information from group description.
+     *
+     * @param groupDesc group description to be used to create group entry
+     */
+    @Override
+    public void storeGroupDescription(GroupDescription groupDesc) {
+        // Check if a group is existing with the same key
+        if (getGroup(groupDesc.deviceId(), groupDesc.appCookie()) != null) {
+            return;
+        }
+
+        if (deviceAuditStatus.get(groupDesc.deviceId()) == null) {
+            // Device group audit has not completed yet
+            // Add this group description to pending group key table
+            // Create a group entry object with Dummy Group ID
+            StoredGroupEntry group = new DefaultGroup(dummyGroupId, groupDesc);
+            group.setState(GroupState.WAITING_AUDIT_COMPLETE);
+            ConcurrentMap<GroupKey, StoredGroupEntry> pendingKeyTable =
+                    getPendingGroupKeyTable(groupDesc.deviceId());
+            pendingKeyTable.put(groupDesc.appCookie(), group);
+            return;
+        }
+
+        storeGroupDescriptionInternal(groupDesc);
+    }
+
+    private void storeGroupDescriptionInternal(GroupDescription groupDesc) {
+        // Check if a group is existing with the same key
+        if (getGroup(groupDesc.deviceId(), groupDesc.appCookie()) != null) {
+            return;
+        }
+
+        GroupId id = null;
+        if (groupDesc.givenGroupId() == null) {
+            // Get a new group identifier
+            id = new DefaultGroupId(getFreeGroupIdValue(groupDesc.deviceId()));
+        } else {
+            id = new DefaultGroupId(groupDesc.givenGroupId());
+        }
+        // Create a group entry object
+        StoredGroupEntry group = new DefaultGroup(id, groupDesc);
+        // Insert the newly created group entry into concurrent key and id maps
+        ConcurrentMap<GroupKey, StoredGroupEntry> keyTable =
+                getGroupKeyTable(groupDesc.deviceId());
+        keyTable.put(groupDesc.appCookie(), group);
+        ConcurrentMap<GroupId, StoredGroupEntry> idTable =
+                getGroupIdTable(groupDesc.deviceId());
+        idTable.put(id, group);
+        notifyDelegate(new GroupEvent(GroupEvent.Type.GROUP_ADD_REQUESTED,
+                                      group));
+    }
+
+    /**
+     * Updates the existing group entry with the information
+     * from group description.
+     *
+     * @param deviceId the device ID
+     * @param oldAppCookie the current group key
+     * @param type update type
+     * @param newBuckets group buckets for updates
+     * @param newAppCookie optional new group key
+     */
+    @Override
+    public void updateGroupDescription(DeviceId deviceId,
+                                GroupKey oldAppCookie,
+                                UpdateType type,
+                                GroupBuckets newBuckets,
+                                GroupKey newAppCookie) {
+        // Check if a group is existing with the provided key
+        Group oldGroup = getGroup(deviceId, oldAppCookie);
+        if (oldGroup == null) {
+            return;
+        }
+
+        List<GroupBucket> newBucketList = getUpdatedBucketList(oldGroup,
+                                                               type,
+                                                               newBuckets);
+        if (newBucketList != null) {
+            // Create a new group object from the old group
+            GroupBuckets updatedBuckets = new GroupBuckets(newBucketList);
+            GroupKey newCookie = (newAppCookie != null) ? newAppCookie : oldAppCookie;
+            GroupDescription updatedGroupDesc = new DefaultGroupDescription(
+                                                        oldGroup.deviceId(),
+                                                        oldGroup.type(),
+                                                        updatedBuckets,
+                                                        newCookie,
+                                                        oldGroup.givenGroupId(),
+                                                        oldGroup.appId());
+            StoredGroupEntry newGroup = new DefaultGroup(oldGroup.id(),
+                                                     updatedGroupDesc);
+            newGroup.setState(GroupState.PENDING_UPDATE);
+            newGroup.setLife(oldGroup.life());
+            newGroup.setPackets(oldGroup.packets());
+            newGroup.setBytes(oldGroup.bytes());
+            // Remove the old entry from maps and add new entry using new key
+            ConcurrentMap<GroupKey, StoredGroupEntry> keyTable =
+                    getGroupKeyTable(oldGroup.deviceId());
+            ConcurrentMap<GroupId, StoredGroupEntry> idTable =
+                    getGroupIdTable(oldGroup.deviceId());
+            keyTable.remove(oldGroup.appCookie());
+            idTable.remove(oldGroup.id());
+            keyTable.put(newGroup.appCookie(), newGroup);
+            idTable.put(newGroup.id(), newGroup);
+            notifyDelegate(new GroupEvent(Type.GROUP_UPDATE_REQUESTED, newGroup));
+        }
+    }
+
+    private List<GroupBucket> getUpdatedBucketList(Group oldGroup,
+                                   UpdateType type,
+                                   GroupBuckets buckets) {
+        GroupBuckets oldBuckets = oldGroup.buckets();
+        List<GroupBucket> newBucketList = new ArrayList<GroupBucket>(
+                oldBuckets.buckets());
+        boolean groupDescUpdated = false;
+
+        if (type == UpdateType.ADD) {
+            // Check if the any of the new buckets are part of
+            // the old bucket list
+            for (GroupBucket addBucket:buckets.buckets()) {
+                if (!newBucketList.contains(addBucket)) {
+                    newBucketList.add(addBucket);
+                    groupDescUpdated = true;
+                }
+            }
+        } else if (type == UpdateType.REMOVE) {
+            // Check if the to be removed buckets are part of the
+            // old bucket list
+            for (GroupBucket removeBucket:buckets.buckets()) {
+                if (newBucketList.contains(removeBucket)) {
+                    newBucketList.remove(removeBucket);
+                    groupDescUpdated = true;
+                }
+            }
+        }
+
+        if (groupDescUpdated) {
+            return newBucketList;
+        } else {
+            return null;
+        }
+    }
+
+    /**
+     * Triggers deleting the existing group entry.
+     *
+     * @param deviceId the device ID
+     * @param appCookie the group key
+     */
+    @Override
+    public void deleteGroupDescription(DeviceId deviceId,
+                                GroupKey appCookie) {
+        // Check if a group is existing with the provided key
+        StoredGroupEntry existing = (groupEntriesByKey.get(deviceId) != null) ?
+                           groupEntriesByKey.get(deviceId).get(appCookie) :
+                           null;
+        if (existing == null) {
+            return;
+        }
+
+        synchronized (existing) {
+            existing.setState(GroupState.PENDING_DELETE);
+        }
+        notifyDelegate(new GroupEvent(Type.GROUP_REMOVE_REQUESTED, existing));
+    }
+
+    /**
+     * Stores a new group entry, or updates an existing entry.
+     *
+     * @param group group entry
+     */
+    @Override
+    public void addOrUpdateGroupEntry(Group group) {
+        // check if this new entry is an update to an existing entry
+        StoredGroupEntry existing = (groupEntriesById.get(
+                      group.deviceId()) != null) ?
+                      groupEntriesById.get(group.deviceId()).get(group.id()) :
+                      null;
+        GroupEvent event = null;
+
+        if (existing != null) {
+            synchronized (existing) {
+                for (GroupBucket bucket:group.buckets().buckets()) {
+                    Optional<GroupBucket> matchingBucket =
+                            existing.buckets().buckets()
+                            .stream()
+                            .filter((existingBucket)->(existingBucket.equals(bucket)))
+                            .findFirst();
+                    if (matchingBucket.isPresent()) {
+                        ((StoredGroupBucketEntry) matchingBucket.
+                                get()).setPackets(bucket.packets());
+                        ((StoredGroupBucketEntry) matchingBucket.
+                                get()).setBytes(bucket.bytes());
+                    } else {
+                        log.warn("addOrUpdateGroupEntry: No matching "
+                                + "buckets to update stats");
+                    }
+                }
+                existing.setLife(group.life());
+                existing.setPackets(group.packets());
+                existing.setBytes(group.bytes());
+                if (existing.state() == GroupState.PENDING_ADD) {
+                    existing.setState(GroupState.ADDED);
+                    event = new GroupEvent(Type.GROUP_ADDED, existing);
+                } else {
+                    if (existing.state() == GroupState.PENDING_UPDATE) {
+                        existing.setState(GroupState.ADDED);
+                    }
+                    event = new GroupEvent(Type.GROUP_UPDATED, existing);
+                }
+            }
+        }
+
+        if (event != null) {
+            notifyDelegate(event);
+        }
+    }
+
+    /**
+     * Removes the group entry from store.
+     *
+     * @param group group entry
+     */
+    @Override
+    public void removeGroupEntry(Group group) {
+        StoredGroupEntry existing = (groupEntriesById.get(
+                         group.deviceId()) != null) ?
+                         groupEntriesById.get(group.deviceId()).get(group.id()) :
+                         null;
+
+        if (existing != null) {
+            ConcurrentMap<GroupKey, StoredGroupEntry> keyTable =
+                    getGroupKeyTable(existing.deviceId());
+            ConcurrentMap<GroupId, StoredGroupEntry> idTable =
+                    getGroupIdTable(existing.deviceId());
+            idTable.remove(existing.id());
+            keyTable.remove(existing.appCookie());
+            notifyDelegate(new GroupEvent(Type.GROUP_REMOVED, existing));
+        }
+    }
+
+    @Override
+    public void deviceInitialAuditCompleted(DeviceId deviceId,
+                                            boolean completed) {
+        synchronized (deviceAuditStatus) {
+            if (completed) {
+                log.debug("deviceInitialAuditCompleted: AUDIT "
+                        + "completed for device {}", deviceId);
+                deviceAuditStatus.put(deviceId, true);
+                // Execute all pending group requests
+                ConcurrentMap<GroupKey, StoredGroupEntry> pendingGroupRequests =
+                        getPendingGroupKeyTable(deviceId);
+                for (Group group:pendingGroupRequests.values()) {
+                    GroupDescription tmp = new DefaultGroupDescription(
+                                                                       group.deviceId(),
+                                                                       group.type(),
+                                                                       group.buckets(),
+                                                                       group.appCookie(),
+                                                                       group.givenGroupId(),
+                                                                       group.appId());
+                    storeGroupDescriptionInternal(tmp);
+                }
+                getPendingGroupKeyTable(deviceId).clear();
+            } else {
+                if (deviceAuditStatus.get(deviceId)) {
+                    log.debug("deviceInitialAuditCompleted: Clearing AUDIT "
+                            + "status for device {}", deviceId);
+                    deviceAuditStatus.put(deviceId, false);
+                }
+            }
+        }
+    }
+
+    @Override
+    public boolean deviceInitialAuditStatus(DeviceId deviceId) {
+        synchronized (deviceAuditStatus) {
+            return (deviceAuditStatus.get(deviceId) != null)
+                    ? deviceAuditStatus.get(deviceId) : false;
+        }
+    }
+
+    @Override
+    public void groupOperationFailed(DeviceId deviceId, GroupOperation operation) {
+
+        StoredGroupEntry existing = (groupEntriesById.get(
+                deviceId) != null) ?
+                groupEntriesById.get(deviceId).get(operation.groupId()) :
+                null;
+
+        if (existing == null) {
+            log.warn("No group entry with ID {} found ", operation.groupId());
+            return;
+        }
+
+        switch (operation.opType()) {
+        case ADD:
+            notifyDelegate(new GroupEvent(Type.GROUP_ADD_FAILED, existing));
+            break;
+        case MODIFY:
+            notifyDelegate(new GroupEvent(Type.GROUP_UPDATE_FAILED, existing));
+            break;
+        case DELETE:
+            notifyDelegate(new GroupEvent(Type.GROUP_REMOVE_FAILED, existing));
+            break;
+        default:
+            log.warn("Unknown group operation type {}", operation.opType());
+        }
+
+        ConcurrentMap<GroupKey, StoredGroupEntry> keyTable =
+                getGroupKeyTable(existing.deviceId());
+        ConcurrentMap<GroupId, StoredGroupEntry> idTable =
+                getGroupIdTable(existing.deviceId());
+        idTable.remove(existing.id());
+        keyTable.remove(existing.appCookie());
+    }
+
+    @Override
+    public void addOrUpdateExtraneousGroupEntry(Group group) {
+        ConcurrentMap<GroupId, Group> extraneousIdTable =
+                getExtraneousGroupIdTable(group.deviceId());
+        extraneousIdTable.put(group.id(), group);
+        // Check the reference counter
+        if (group.referenceCount() == 0) {
+            notifyDelegate(new GroupEvent(Type.GROUP_REMOVE_REQUESTED, group));
+        }
+    }
+
+    @Override
+    public void removeExtraneousGroupEntry(Group group) {
+        ConcurrentMap<GroupId, Group> extraneousIdTable =
+                getExtraneousGroupIdTable(group.deviceId());
+        extraneousIdTable.remove(group.id());
+    }
+
+    @Override
+    public Iterable<Group> getExtraneousGroups(DeviceId deviceId) {
+        // flatten and make iterator unmodifiable
+        return FluentIterable.from(
+                  getExtraneousGroupIdTable(deviceId).values());
+    }
+
+    @Override
+    public void pushGroupMetrics(DeviceId deviceId,
+                                 Collection<Group> groupEntries) {
+        boolean deviceInitialAuditStatus =
+                deviceInitialAuditStatus(deviceId);
+        Set<Group> southboundGroupEntries =
+                Sets.newHashSet(groupEntries);
+        Set<Group> storedGroupEntries =
+                Sets.newHashSet(getGroups(deviceId));
+        Set<Group> extraneousStoredEntries =
+                Sets.newHashSet(getExtraneousGroups(deviceId));
+
+        log.trace("pushGroupMetrics: Displaying all ({}) "
+                + "southboundGroupEntries for device {}",
+                  southboundGroupEntries.size(),
+                  deviceId);
+        for (Iterator<Group> it = southboundGroupEntries.iterator(); it.hasNext();) {
+            Group group = it.next();
+            log.trace("Group {} in device {}", group, deviceId);
+        }
+
+        log.trace("Displaying all ({}) stored group entries for device {}",
+                  storedGroupEntries.size(),
+                  deviceId);
+        for (Iterator<Group> it1 = storedGroupEntries.iterator();
+                it1.hasNext();) {
+            Group group = it1.next();
+            log.trace("Stored Group {} for device {}", group, deviceId);
+        }
+
+        for (Iterator<Group> it2 = southboundGroupEntries.iterator(); it2.hasNext();) {
+            Group group = it2.next();
+            if (storedGroupEntries.remove(group)) {
+                // we both have the group, let's update some info then.
+                log.trace("Group AUDIT: group {} exists "
+                        + "in both planes for device {}",
+                        group.id(), deviceId);
+                groupAdded(group);
+                it2.remove();
+            }
+        }
+        for (Group group : southboundGroupEntries) {
+            if (getGroup(group.deviceId(), group.id()) != null) {
+                // There is a group existing with the same id
+                // It is possible that group update is
+                // in progress while we got a stale info from switch
+                if (!storedGroupEntries.remove(getGroup(
+                             group.deviceId(), group.id()))) {
+                    log.warn("Group AUDIT: Inconsistent state:"
+                            + "Group exists in ID based table while "
+                            + "not present in key based table");
+                }
+            } else {
+                // there are groups in the switch that aren't in the store
+                log.trace("Group AUDIT: extraneous group {} exists "
+                        + "in data plane for device {}",
+                        group.id(), deviceId);
+                extraneousStoredEntries.remove(group);
+                extraneousGroup(group);
+            }
+        }
+        for (Group group : storedGroupEntries) {
+            // there are groups in the store that aren't in the switch
+            log.trace("Group AUDIT: group {} missing "
+                    + "in data plane for device {}",
+                    group.id(), deviceId);
+            groupMissing(group);
+        }
+        for (Group group : extraneousStoredEntries) {
+            // there are groups in the extraneous store that
+            // aren't in the switch
+            log.trace("Group AUDIT: clearing extransoeus group {} "
+                    + "from store for device {}",
+                    group.id(), deviceId);
+            removeExtraneousGroupEntry(group);
+        }
+
+        if (!deviceInitialAuditStatus) {
+            log.debug("Group AUDIT: Setting device {} initial "
+                    + "AUDIT completed", deviceId);
+            deviceInitialAuditCompleted(deviceId, true);
+        }
+    }
+
+    private void groupMissing(Group group) {
+        switch (group.state()) {
+            case PENDING_DELETE:
+                log.debug("Group {} delete confirmation from device {}",
+                          group, group.deviceId());
+                removeGroupEntry(group);
+                break;
+            case ADDED:
+            case PENDING_ADD:
+            case PENDING_UPDATE:
+                log.debug("Group {} is in store but not on device {}",
+                          group, group.deviceId());
+                StoredGroupEntry existing = (groupEntriesById.get(
+                              group.deviceId()) != null) ?
+                              groupEntriesById.get(group.deviceId()).get(group.id()) :
+                              null;
+                log.trace("groupMissing: group "
+                        + "entry {} in device {} moving "
+                        + "from {} to PENDING_ADD",
+                        existing.id(),
+                        existing.deviceId(),
+                        existing.state());
+                existing.setState(Group.GroupState.PENDING_ADD);
+                notifyDelegate(new GroupEvent(GroupEvent.Type.GROUP_ADD_REQUESTED,
+                                              group));
+                break;
+            default:
+                log.debug("Group {} has not been installed.", group);
+                break;
+        }
+    }
+
+    private void extraneousGroup(Group group) {
+        log.debug("Group {} is on device {} but not in store.",
+                  group, group.deviceId());
+        addOrUpdateExtraneousGroupEntry(group);
+    }
+
+    private void groupAdded(Group group) {
+        log.trace("Group {} Added or Updated in device {}",
+                  group, group.deviceId());
+        addOrUpdateGroupEntry(group);
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleGroupStoreTest.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleGroupStoreTest.java
new file mode 100644
index 0000000..dd6c8a5
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleGroupStoreTest.java
@@ -0,0 +1,482 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import static org.junit.Assert.assertEquals;
+import static org.onosproject.net.DeviceId.deviceId;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.packet.MacAddress;
+import org.onlab.packet.MplsLabel;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.DefaultApplicationId;
+import org.onosproject.core.GroupId;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.flow.DefaultTrafficTreatment;
+import org.onosproject.net.flow.TrafficTreatment;
+import org.onosproject.net.group.DefaultGroup;
+import org.onosproject.net.group.DefaultGroupBucket;
+import org.onosproject.net.group.DefaultGroupDescription;
+import org.onosproject.net.group.DefaultGroupKey;
+import org.onosproject.net.group.Group;
+import org.onosproject.net.group.GroupBucket;
+import org.onosproject.net.group.GroupBuckets;
+import org.onosproject.net.group.GroupDescription;
+import org.onosproject.net.group.GroupEvent;
+import org.onosproject.net.group.GroupKey;
+import org.onosproject.net.group.GroupOperation;
+import org.onosproject.net.group.GroupStore.UpdateType;
+import org.onosproject.net.group.GroupStoreDelegate;
+import org.onosproject.net.group.StoredGroupBucketEntry;
+import org.onosproject.net.group.StoredGroupEntry;
+
+import com.google.common.collect.Iterables;
+
+/**
+ * Test of the simple DeviceStore implementation.
+ */
+public class SimpleGroupStoreTest {
+
+    private SimpleGroupStore simpleGroupStore;
+    private final ApplicationId appId =
+            new DefaultApplicationId(2, "org.groupstore.test");
+
+    public static final DeviceId D1 = deviceId("of:1");
+
+    @Before
+    public void setUp() throws Exception {
+        simpleGroupStore = new SimpleGroupStore();
+        simpleGroupStore.activate();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        simpleGroupStore.deactivate();
+    }
+
+    private class InternalGroupStoreDelegate
+                implements GroupStoreDelegate {
+        private GroupId createdGroupId = null;
+        private GroupKey createdGroupKey;
+        private GroupBuckets createdBuckets;
+        private GroupEvent.Type expectedEvent;
+
+        public InternalGroupStoreDelegate(GroupKey key,
+                                          GroupBuckets buckets,
+                                          GroupEvent.Type expectedEvent) {
+            this.createdBuckets = buckets;
+            this.createdGroupKey = key;
+            this.expectedEvent = expectedEvent;
+        }
+        @Override
+        public void notify(GroupEvent event) {
+            assertEquals(expectedEvent, event.type());
+            assertEquals(Group.Type.SELECT, event.subject().type());
+            assertEquals(D1, event.subject().deviceId());
+            assertEquals(createdGroupKey, event.subject().appCookie());
+            assertEquals(createdBuckets.buckets(), event.subject().buckets().buckets());
+            if (expectedEvent == GroupEvent.Type.GROUP_ADD_REQUESTED) {
+                createdGroupId = event.subject().id();
+                assertEquals(Group.GroupState.PENDING_ADD,
+                             event.subject().state());
+            } else if (expectedEvent == GroupEvent.Type.GROUP_ADDED) {
+                createdGroupId = event.subject().id();
+                assertEquals(Group.GroupState.ADDED,
+                             event.subject().state());
+            } else if (expectedEvent == GroupEvent.Type.GROUP_UPDATED) {
+                createdGroupId = event.subject().id();
+                assertEquals(true,
+                             event.subject().buckets().
+                             buckets().containsAll(createdBuckets.buckets()));
+                assertEquals(true,
+                             createdBuckets.buckets().
+                             containsAll(event.subject().buckets().buckets()));
+                for (GroupBucket bucket:event.subject().buckets().buckets()) {
+                    Optional<GroupBucket> matched = createdBuckets.buckets()
+                            .stream()
+                            .filter((expected) -> expected.equals(bucket))
+                            .findFirst();
+                    assertEquals(matched.get().packets(),
+                                 bucket.packets());
+                    assertEquals(matched.get().bytes(),
+                                 bucket.bytes());
+                }
+                assertEquals(Group.GroupState.ADDED,
+                             event.subject().state());
+            } else if (expectedEvent == GroupEvent.Type.GROUP_UPDATE_REQUESTED) {
+                assertEquals(Group.GroupState.PENDING_UPDATE,
+                             event.subject().state());
+            } else if (expectedEvent == GroupEvent.Type.GROUP_REMOVE_REQUESTED) {
+                assertEquals(Group.GroupState.PENDING_DELETE,
+                             event.subject().state());
+            } else if (expectedEvent == GroupEvent.Type.GROUP_REMOVED) {
+                createdGroupId = event.subject().id();
+                assertEquals(Group.GroupState.PENDING_DELETE,
+                             event.subject().state());
+            } else if (expectedEvent == GroupEvent.Type.GROUP_ADD_FAILED) {
+                createdGroupId = event.subject().id();
+                assertEquals(Group.GroupState.PENDING_ADD,
+                        event.subject().state());
+            } else if (expectedEvent == GroupEvent.Type.GROUP_UPDATE_FAILED) {
+                createdGroupId = event.subject().id();
+                assertEquals(Group.GroupState.PENDING_UPDATE,
+                        event.subject().state());
+            } else if (expectedEvent == GroupEvent.Type.GROUP_REMOVE_FAILED) {
+                createdGroupId = event.subject().id();
+                assertEquals(Group.GroupState.PENDING_DELETE,
+                        event.subject().state());
+            }
+        }
+
+        public void verifyGroupId(GroupId id) {
+            assertEquals(createdGroupId, id);
+        }
+    }
+
+    /**
+     * Tests group store operations. The following operations are tested:
+     * a)Tests device group audit completion status change
+     * b)Tests storeGroup operation
+     * c)Tests getGroupCount operation
+     * d)Tests getGroup operation
+     * e)Tests getGroups operation
+     * f)Tests addOrUpdateGroupEntry operation from southbound
+     * g)Tests updateGroupDescription for ADD operation from northbound
+     * h)Tests updateGroupDescription for REMOVE operation from northbound
+     * i)Tests deleteGroupDescription operation from northbound
+     * j)Tests removeGroupEntry operation from southbound
+     */
+    @Test
+    public void testGroupStoreOperations() {
+        // Set the Device AUDIT completed in the store
+        simpleGroupStore.deviceInitialAuditCompleted(D1, true);
+
+        // Testing storeGroup operation
+        GroupKey newKey = new DefaultGroupKey("group1".getBytes());
+        testStoreAndGetGroup(newKey);
+
+        // Testing addOrUpdateGroupEntry operation from southbound
+        GroupKey currKey = newKey;
+        testAddGroupEntryFromSB(currKey);
+
+        // Testing updateGroupDescription for ADD operation from northbound
+        newKey = new DefaultGroupKey("group1AddBuckets".getBytes());
+        testAddBuckets(currKey, newKey);
+
+        // Testing updateGroupDescription for REMOVE operation from northbound
+        currKey = newKey;
+        newKey = new DefaultGroupKey("group1RemoveBuckets".getBytes());
+        testRemoveBuckets(currKey, newKey);
+
+        // Testing addOrUpdateGroupEntry operation from southbound
+        currKey = newKey;
+        testUpdateGroupEntryFromSB(currKey);
+
+        // Testing deleteGroupDescription operation from northbound
+        testDeleteGroup(currKey);
+
+        // Testing removeGroupEntry operation from southbound
+        testRemoveGroupFromSB(currKey);
+    }
+
+    // Testing storeGroup operation
+    private void testStoreAndGetGroup(GroupKey key) {
+        PortNumber[] ports = {PortNumber.portNumber(31),
+                              PortNumber.portNumber(32)};
+        List<PortNumber> outPorts = new ArrayList<PortNumber>();
+        outPorts.addAll(Arrays.asList(ports));
+
+        List<GroupBucket> buckets = new ArrayList<GroupBucket>();
+        for (PortNumber portNumber: outPorts) {
+            TrafficTreatment.Builder tBuilder = DefaultTrafficTreatment.builder();
+            tBuilder.setOutput(portNumber)
+                    .setEthDst(MacAddress.valueOf("00:00:00:00:00:02"))
+                    .setEthSrc(MacAddress.valueOf("00:00:00:00:00:01"))
+                    .pushMpls()
+                    .setMpls(MplsLabel.mplsLabel(106));
+            buckets.add(DefaultGroupBucket.createSelectGroupBucket(
+                                                        tBuilder.build()));
+        }
+        GroupBuckets groupBuckets = new GroupBuckets(buckets);
+        GroupDescription groupDesc = new DefaultGroupDescription(
+                                                 D1,
+                                                 Group.Type.SELECT,
+                                                 groupBuckets,
+                                                 key,
+                                                 null,
+                                                 appId);
+        InternalGroupStoreDelegate checkStoreGroupDelegate =
+                new InternalGroupStoreDelegate(key,
+                                               groupBuckets,
+                                               GroupEvent.Type.GROUP_ADD_REQUESTED);
+        simpleGroupStore.setDelegate(checkStoreGroupDelegate);
+        // Testing storeGroup operation
+        simpleGroupStore.storeGroupDescription(groupDesc);
+
+        // Testing getGroupCount operation
+        assertEquals(1, simpleGroupStore.getGroupCount(D1));
+
+        // Testing getGroup operation
+        Group createdGroup = simpleGroupStore.getGroup(D1, key);
+        checkStoreGroupDelegate.verifyGroupId(createdGroup.id());
+
+        // Testing getGroups operation
+        Iterable<Group> createdGroups = simpleGroupStore.getGroups(D1);
+        int groupCount = 0;
+        for (Group group:createdGroups) {
+            checkStoreGroupDelegate.verifyGroupId(group.id());
+            groupCount++;
+        }
+        assertEquals(1, groupCount);
+        simpleGroupStore.unsetDelegate(checkStoreGroupDelegate);
+    }
+
+    // Testing addOrUpdateGroupEntry operation from southbound
+    private void testAddGroupEntryFromSB(GroupKey currKey) {
+        Group existingGroup = simpleGroupStore.getGroup(D1, currKey);
+
+        InternalGroupStoreDelegate addGroupEntryDelegate =
+                new InternalGroupStoreDelegate(currKey,
+                                               existingGroup.buckets(),
+                                               GroupEvent.Type.GROUP_ADDED);
+        simpleGroupStore.setDelegate(addGroupEntryDelegate);
+        simpleGroupStore.addOrUpdateGroupEntry(existingGroup);
+        simpleGroupStore.unsetDelegate(addGroupEntryDelegate);
+    }
+
+    // Testing addOrUpdateGroupEntry operation from southbound
+    private void testUpdateGroupEntryFromSB(GroupKey currKey) {
+        Group existingGroup = simpleGroupStore.getGroup(D1, currKey);
+        int totalPkts = 0;
+        int totalBytes = 0;
+        List<GroupBucket> newBucketList = new ArrayList<GroupBucket>();
+        for (GroupBucket bucket:existingGroup.buckets().buckets()) {
+            StoredGroupBucketEntry newBucket =
+                    (StoredGroupBucketEntry)
+                    DefaultGroupBucket.createSelectGroupBucket(bucket.treatment());
+            newBucket.setPackets(10);
+            newBucket.setBytes(10 * 256 * 8);
+            totalPkts += 10;
+            totalBytes += 10 * 256 * 8;
+            newBucketList.add(newBucket);
+        }
+        GroupBuckets updatedBuckets = new GroupBuckets(newBucketList);
+        Group updatedGroup = new DefaultGroup(existingGroup.id(),
+                                              existingGroup.deviceId(),
+                                              existingGroup.type(),
+                                              updatedBuckets);
+        ((StoredGroupEntry) updatedGroup).setPackets(totalPkts);
+        ((StoredGroupEntry) updatedGroup).setBytes(totalBytes);
+
+        InternalGroupStoreDelegate updateGroupEntryDelegate =
+                new InternalGroupStoreDelegate(currKey,
+                                               updatedBuckets,
+                                               GroupEvent.Type.GROUP_UPDATED);
+        simpleGroupStore.setDelegate(updateGroupEntryDelegate);
+        simpleGroupStore.addOrUpdateGroupEntry(updatedGroup);
+        simpleGroupStore.unsetDelegate(updateGroupEntryDelegate);
+    }
+
+    // Testing updateGroupDescription for ADD operation from northbound
+    private void testAddBuckets(GroupKey currKey, GroupKey addKey) {
+        Group existingGroup = simpleGroupStore.getGroup(D1, currKey);
+        List<GroupBucket> buckets = new ArrayList<GroupBucket>();
+        buckets.addAll(existingGroup.buckets().buckets());
+
+        PortNumber[] newNeighborPorts = {PortNumber.portNumber(41),
+                                         PortNumber.portNumber(42)};
+        List<PortNumber> newOutPorts = new ArrayList<PortNumber>();
+        newOutPorts.addAll(Collections.singletonList(newNeighborPorts[0]));
+
+        List<GroupBucket> toAddBuckets = new ArrayList<GroupBucket>();
+        for (PortNumber portNumber: newOutPorts) {
+            TrafficTreatment.Builder tBuilder = DefaultTrafficTreatment.builder();
+            tBuilder.setOutput(portNumber)
+                    .setEthDst(MacAddress.valueOf("00:00:00:00:00:03"))
+                    .setEthSrc(MacAddress.valueOf("00:00:00:00:00:01"))
+                    .pushMpls()
+                    .setMpls(MplsLabel.mplsLabel(106));
+            toAddBuckets.add(DefaultGroupBucket.createSelectGroupBucket(
+                                                        tBuilder.build()));
+        }
+        GroupBuckets toAddGroupBuckets = new GroupBuckets(toAddBuckets);
+        buckets.addAll(toAddBuckets);
+        GroupBuckets updatedGroupBuckets = new GroupBuckets(buckets);
+        InternalGroupStoreDelegate updateGroupDescDelegate =
+                new InternalGroupStoreDelegate(addKey,
+                                               updatedGroupBuckets,
+                                               GroupEvent.Type.GROUP_UPDATE_REQUESTED);
+        simpleGroupStore.setDelegate(updateGroupDescDelegate);
+        simpleGroupStore.updateGroupDescription(D1,
+                                                currKey,
+                                                UpdateType.ADD,
+                                                toAddGroupBuckets,
+                                                addKey);
+        simpleGroupStore.unsetDelegate(updateGroupDescDelegate);
+    }
+
+    // Testing updateGroupDescription for REMOVE operation from northbound
+    private void testRemoveBuckets(GroupKey currKey, GroupKey removeKey) {
+        Group existingGroup = simpleGroupStore.getGroup(D1, currKey);
+        List<GroupBucket> buckets = new ArrayList<GroupBucket>();
+        buckets.addAll(existingGroup.buckets().buckets());
+
+        List<GroupBucket> toRemoveBuckets = new ArrayList<GroupBucket>();
+
+        // There should be 4 buckets in the current group
+        toRemoveBuckets.add(buckets.remove(0));
+        toRemoveBuckets.add(buckets.remove(1));
+        GroupBuckets toRemoveGroupBuckets = new GroupBuckets(toRemoveBuckets);
+
+        GroupBuckets remainingGroupBuckets = new GroupBuckets(buckets);
+        InternalGroupStoreDelegate removeGroupDescDelegate =
+                new InternalGroupStoreDelegate(removeKey,
+                                               remainingGroupBuckets,
+                                               GroupEvent.Type.GROUP_UPDATE_REQUESTED);
+        simpleGroupStore.setDelegate(removeGroupDescDelegate);
+        simpleGroupStore.updateGroupDescription(D1,
+                                                currKey,
+                                                UpdateType.REMOVE,
+                                                toRemoveGroupBuckets,
+                                                removeKey);
+        simpleGroupStore.unsetDelegate(removeGroupDescDelegate);
+    }
+
+    // Testing deleteGroupDescription operation from northbound
+    private void testDeleteGroup(GroupKey currKey) {
+        Group existingGroup = simpleGroupStore.getGroup(D1, currKey);
+        InternalGroupStoreDelegate deleteGroupDescDelegate =
+                new InternalGroupStoreDelegate(currKey,
+                                               existingGroup.buckets(),
+                                               GroupEvent.Type.GROUP_REMOVE_REQUESTED);
+        simpleGroupStore.setDelegate(deleteGroupDescDelegate);
+        simpleGroupStore.deleteGroupDescription(D1, currKey);
+        simpleGroupStore.unsetDelegate(deleteGroupDescDelegate);
+    }
+
+    // Testing removeGroupEntry operation from southbound
+    private void testRemoveGroupFromSB(GroupKey currKey) {
+        Group existingGroup = simpleGroupStore.getGroup(D1, currKey);
+        InternalGroupStoreDelegate removeGroupEntryDelegate =
+                new InternalGroupStoreDelegate(currKey,
+                                               existingGroup.buckets(),
+                                               GroupEvent.Type.GROUP_REMOVED);
+        simpleGroupStore.setDelegate(removeGroupEntryDelegate);
+        simpleGroupStore.removeGroupEntry(existingGroup);
+
+        // Testing getGroup operation
+        existingGroup = simpleGroupStore.getGroup(D1, currKey);
+        assertEquals(null, existingGroup);
+        assertEquals(0, Iterables.size(simpleGroupStore.getGroups(D1)));
+        assertEquals(0, simpleGroupStore.getGroupCount(D1));
+
+        simpleGroupStore.unsetDelegate(removeGroupEntryDelegate);
+    }
+
+    @Test
+    public void testGroupOperationFailure() {
+
+        simpleGroupStore.deviceInitialAuditCompleted(D1, true);
+
+        ApplicationId appId =
+                new DefaultApplicationId(2, "org.groupstore.test");
+        GroupKey key = new DefaultGroupKey("group1".getBytes());
+        PortNumber[] ports = {PortNumber.portNumber(31),
+                PortNumber.portNumber(32)};
+        List<PortNumber> outPorts = new ArrayList<PortNumber>();
+        outPorts.add(ports[0]);
+        outPorts.add(ports[1]);
+
+        List<GroupBucket> buckets = new ArrayList<GroupBucket>();
+        for (PortNumber portNumber: outPorts) {
+            TrafficTreatment.Builder tBuilder = DefaultTrafficTreatment.builder();
+            tBuilder.setOutput(portNumber)
+                    .setEthDst(MacAddress.valueOf("00:00:00:00:00:02"))
+                    .setEthSrc(MacAddress.valueOf("00:00:00:00:00:01"))
+                    .pushMpls()
+                    .setMpls(MplsLabel.mplsLabel(106));
+            buckets.add(DefaultGroupBucket.createSelectGroupBucket(
+                    tBuilder.build()));
+        }
+        GroupBuckets groupBuckets = new GroupBuckets(buckets);
+        GroupDescription groupDesc = new DefaultGroupDescription(
+                D1,
+                Group.Type.SELECT,
+                groupBuckets,
+                key,
+                null,
+                appId);
+        InternalGroupStoreDelegate checkStoreGroupDelegate =
+                new InternalGroupStoreDelegate(key,
+                        groupBuckets,
+                        GroupEvent.Type.GROUP_ADD_REQUESTED);
+        simpleGroupStore.setDelegate(checkStoreGroupDelegate);
+        // Testing storeGroup operation
+        simpleGroupStore.storeGroupDescription(groupDesc);
+        simpleGroupStore.unsetDelegate(checkStoreGroupDelegate);
+
+        // Testing Group add operation failure
+        Group createdGroup = simpleGroupStore.getGroup(D1, key);
+        checkStoreGroupDelegate.verifyGroupId(createdGroup.id());
+
+        GroupOperation groupAddOp = GroupOperation.
+                createAddGroupOperation(createdGroup.id(),
+                        createdGroup.type(),
+                        createdGroup.buckets());
+        InternalGroupStoreDelegate checkGroupAddFailureDelegate =
+                new InternalGroupStoreDelegate(key,
+                        groupBuckets,
+                        GroupEvent.Type.GROUP_ADD_FAILED);
+        simpleGroupStore.setDelegate(checkGroupAddFailureDelegate);
+        simpleGroupStore.groupOperationFailed(D1, groupAddOp);
+
+
+        // Testing Group modify operation failure
+        simpleGroupStore.unsetDelegate(checkGroupAddFailureDelegate);
+        GroupOperation groupModOp = GroupOperation.
+                createModifyGroupOperation(createdGroup.id(),
+                        createdGroup.type(),
+                        createdGroup.buckets());
+        InternalGroupStoreDelegate checkGroupModFailureDelegate =
+                new InternalGroupStoreDelegate(key,
+                        groupBuckets,
+                        GroupEvent.Type.GROUP_UPDATE_FAILED);
+        simpleGroupStore.setDelegate(checkGroupModFailureDelegate);
+        simpleGroupStore.groupOperationFailed(D1, groupModOp);
+
+        // Testing Group modify operation failure
+        simpleGroupStore.unsetDelegate(checkGroupModFailureDelegate);
+        GroupOperation groupDelOp = GroupOperation.
+                createDeleteGroupOperation(createdGroup.id(),
+                        createdGroup.type());
+        InternalGroupStoreDelegate checkGroupDelFailureDelegate =
+                new InternalGroupStoreDelegate(key,
+                        groupBuckets,
+                        GroupEvent.Type.GROUP_REMOVE_FAILED);
+        simpleGroupStore.setDelegate(checkGroupDelFailureDelegate);
+        simpleGroupStore.groupOperationFailed(D1, groupDelOp);
+    }
+}
+
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleHostStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleHostStore.java
new file mode 100644
index 0000000..f5604f6
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleHostStore.java
@@ -0,0 +1,293 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import static org.onosproject.net.DefaultAnnotations.merge;
+import static org.onosproject.net.host.HostEvent.Type.HOST_ADDED;
+import static org.onosproject.net.host.HostEvent.Type.HOST_MOVED;
+import static org.onosproject.net.host.HostEvent.Type.HOST_REMOVED;
+import static org.onosproject.net.host.HostEvent.Type.HOST_UPDATED;
+import static org.slf4j.LoggerFactory.getLogger;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.net.Annotations;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DefaultAnnotations;
+import org.onosproject.net.DefaultHost;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Host;
+import org.onosproject.net.HostId;
+import org.onosproject.net.HostLocation;
+import org.onosproject.net.host.HostDescription;
+import org.onosproject.net.host.HostEvent;
+import org.onosproject.net.host.HostStore;
+import org.onosproject.net.host.HostStoreDelegate;
+import org.onosproject.net.host.PortAddresses;
+import org.onosproject.net.provider.ProviderId;
+import org.onosproject.store.AbstractStore;
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.MacAddress;
+import org.onlab.packet.VlanId;
+import org.slf4j.Logger;
+
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Multimap;
+import com.google.common.collect.Multimaps;
+import com.google.common.collect.SetMultimap;
+
+// TODO: multi-provider, annotation not supported.
+/**
+ * Manages inventory of end-station hosts using trivial in-memory
+ * implementation.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleHostStore
+        extends AbstractStore<HostEvent, HostStoreDelegate>
+        implements HostStore {
+
+    private final Logger log = getLogger(getClass());
+
+    // Host inventory
+    private final Map<HostId, StoredHost> hosts = new ConcurrentHashMap<>(2000000, 0.75f, 16);
+
+    // Hosts tracked by their location
+    private final Multimap<ConnectPoint, Host> locations = HashMultimap.create();
+
+    private final SetMultimap<ConnectPoint, PortAddresses> portAddresses =
+            Multimaps.synchronizedSetMultimap(
+                    HashMultimap.<ConnectPoint, PortAddresses>create());
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        log.info("Stopped");
+    }
+
+    @Override
+    public HostEvent createOrUpdateHost(ProviderId providerId, HostId hostId,
+                                        HostDescription hostDescription) {
+        StoredHost host = hosts.get(hostId);
+        if (host == null) {
+            return createHost(providerId, hostId, hostDescription);
+        }
+        return updateHost(providerId, host, hostDescription);
+    }
+
+    // creates a new host and sends HOST_ADDED
+    private HostEvent createHost(ProviderId providerId, HostId hostId,
+                                 HostDescription descr) {
+        StoredHost newhost = new StoredHost(providerId, hostId,
+                                            descr.hwAddress(),
+                                            descr.vlan(),
+                                            descr.location(),
+                                            ImmutableSet.copyOf(descr.ipAddress()),
+                                            descr.annotations());
+        synchronized (this) {
+            hosts.put(hostId, newhost);
+            locations.put(descr.location(), newhost);
+        }
+        return new HostEvent(HOST_ADDED, newhost);
+    }
+
+    // checks for type of update to host, sends appropriate event
+    private HostEvent updateHost(ProviderId providerId, StoredHost host,
+                                 HostDescription descr) {
+        HostEvent event;
+        if (!host.location().equals(descr.location())) {
+            host.setLocation(descr.location());
+            return new HostEvent(HOST_MOVED, host);
+        }
+
+        if (host.ipAddresses().containsAll(descr.ipAddress()) &&
+                descr.annotations().keys().isEmpty()) {
+            return null;
+        }
+
+        Set<IpAddress> addresses = new HashSet<>(host.ipAddresses());
+        addresses.addAll(descr.ipAddress());
+        Annotations annotations = merge((DefaultAnnotations) host.annotations(),
+                                        descr.annotations());
+        StoredHost updated = new StoredHost(providerId, host.id(),
+                                            host.mac(), host.vlan(),
+                                            descr.location(), addresses,
+                                            annotations);
+        event = new HostEvent(HOST_UPDATED, updated);
+        synchronized (this) {
+            hosts.put(host.id(), updated);
+            locations.remove(host.location(), host);
+            locations.put(updated.location(), updated);
+        }
+        return event;
+    }
+
+    @Override
+    public HostEvent removeHost(HostId hostId) {
+        synchronized (this) {
+            Host host = hosts.remove(hostId);
+            if (host != null) {
+                locations.remove((host.location()), host);
+                return new HostEvent(HOST_REMOVED, host);
+            }
+            return null;
+        }
+    }
+
+    @Override
+    public int getHostCount() {
+        return hosts.size();
+    }
+
+    @Override
+    public Iterable<Host> getHosts() {
+        return ImmutableSet.<Host>copyOf(hosts.values());
+    }
+
+    @Override
+    public Host getHost(HostId hostId) {
+        return hosts.get(hostId);
+    }
+
+    @Override
+    public Set<Host> getHosts(VlanId vlanId) {
+        Set<Host> vlanset = new HashSet<>();
+        for (Host h : hosts.values()) {
+            if (h.vlan().equals(vlanId)) {
+                vlanset.add(h);
+            }
+        }
+        return vlanset;
+    }
+
+    @Override
+    public Set<Host> getHosts(MacAddress mac) {
+        Set<Host> macset = new HashSet<>();
+        for (Host h : hosts.values()) {
+            if (h.mac().equals(mac)) {
+                macset.add(h);
+            }
+        }
+        return macset;
+    }
+
+    @Override
+    public Set<Host> getHosts(IpAddress ip) {
+        Set<Host> ipset = new HashSet<>();
+        for (Host h : hosts.values()) {
+            if (h.ipAddresses().contains(ip)) {
+                ipset.add(h);
+            }
+        }
+        return ipset;
+    }
+
+    @Override
+    public Set<Host> getConnectedHosts(ConnectPoint connectPoint) {
+        return ImmutableSet.copyOf(locations.get(connectPoint));
+    }
+
+    @Override
+    public Set<Host> getConnectedHosts(DeviceId deviceId) {
+        Set<Host> hostset = new HashSet<>();
+        for (ConnectPoint p : locations.keySet()) {
+            if (p.deviceId().equals(deviceId)) {
+                hostset.addAll(locations.get(p));
+            }
+        }
+        return hostset;
+    }
+
+    @Override
+    public void updateAddressBindings(PortAddresses addresses) {
+        portAddresses.put(addresses.connectPoint(), addresses);
+    }
+
+    @Override
+    public void removeAddressBindings(PortAddresses addresses) {
+        portAddresses.remove(addresses.connectPoint(), addresses);
+    }
+
+    @Override
+    public void clearAddressBindings(ConnectPoint connectPoint) {
+        portAddresses.removeAll(connectPoint);
+    }
+
+    @Override
+    public Set<PortAddresses> getAddressBindings() {
+        synchronized (portAddresses) {
+            return ImmutableSet.copyOf(portAddresses.values());
+        }
+    }
+
+    @Override
+    public Set<PortAddresses> getAddressBindingsForPort(ConnectPoint connectPoint) {
+        synchronized (portAddresses) {
+            Set<PortAddresses> addresses = portAddresses.get(connectPoint);
+
+            if (addresses == null) {
+                return Collections.emptySet();
+            } else {
+                return ImmutableSet.copyOf(addresses);
+            }
+        }
+    }
+
+    // Auxiliary extension to allow location to mutate.
+    private static final class StoredHost extends DefaultHost {
+        private HostLocation location;
+
+        /**
+         * Creates an end-station host using the supplied information.
+         *
+         * @param providerId  provider identity
+         * @param id          host identifier
+         * @param mac         host MAC address
+         * @param vlan        host VLAN identifier
+         * @param location    host location
+         * @param ips         host IP addresses
+         * @param annotations optional key/value annotations
+         */
+        public StoredHost(ProviderId providerId, HostId id,
+                          MacAddress mac, VlanId vlan, HostLocation location,
+                          Set<IpAddress> ips, Annotations... annotations) {
+            super(providerId, id, mac, vlan, location, ips, annotations);
+            this.location = location;
+        }
+
+        void setLocation(HostLocation location) {
+            this.location = location;
+        }
+
+        @Override
+        public HostLocation location() {
+            return location;
+        }
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleIdBlockStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleIdBlockStore.java
new file mode 100644
index 0000000..3f7e563
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleIdBlockStore.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.core.IdBlock;
+import org.onosproject.core.IdBlockStore;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * Simple implementation of id block store.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleIdBlockStore implements IdBlockStore {
+
+    private static final long DEFAULT_BLOCK_SIZE = 0x1000L;
+
+    private final Map<String, AtomicLong> topicBlocks = new ConcurrentHashMap<>();
+
+    @Override
+    public synchronized IdBlock getIdBlock(String topic) {
+        AtomicLong blockGenerator = topicBlocks.get(topic);
+        if (blockGenerator == null) {
+            blockGenerator = new AtomicLong(0);
+            topicBlocks.put(topic, blockGenerator);
+        }
+        Long blockBase = blockGenerator.getAndAdd(DEFAULT_BLOCK_SIZE);
+        return new IdBlock(blockBase, DEFAULT_BLOCK_SIZE);
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleIntentStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleIntentStore.java
new file mode 100644
index 0000000..9f95966
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleIntentStore.java
@@ -0,0 +1,212 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.net.intent.Intent;
+import org.onosproject.net.intent.IntentData;
+import org.onosproject.net.intent.IntentEvent;
+import org.onosproject.net.intent.IntentState;
+import org.onosproject.net.intent.IntentStore;
+import org.onosproject.net.intent.IntentStoreDelegate;
+import org.onosproject.net.intent.Key;
+import org.onosproject.store.AbstractStore;
+import org.slf4j.Logger;
+
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.onosproject.net.intent.IntentState.PURGE_REQ;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Simple single-instance implementation of the intent store.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleIntentStore
+        extends AbstractStore<IntentEvent, IntentStoreDelegate>
+        implements IntentStore {
+
+    private final Logger log = getLogger(getClass());
+
+    private final Map<Key, IntentData> current = Maps.newConcurrentMap();
+    private final Map<Key, IntentData> pending = Maps.newConcurrentMap();
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        log.info("Stopped");
+    }
+
+    @Override
+    public long getIntentCount() {
+        return current.size();
+    }
+
+    @Override
+    public Iterable<Intent> getIntents() {
+        return current.values().stream()
+                .map(IntentData::intent)
+                .collect(Collectors.toList());
+    }
+
+    @Override
+    public Iterable<IntentData> getIntentData(boolean localOnly, long olderThan) {
+        if (localOnly || olderThan > 0) {
+            long older = System.nanoTime() - olderThan * 1_000_000; //convert ms to ns
+            final SystemClockTimestamp time = new SystemClockTimestamp(older);
+            return current.values().stream()
+                    .filter(data -> data.version().isOlderThan(time) &&
+                            (!localOnly || isMaster(data.key())))
+                    .collect(Collectors.toList());
+        }
+        return Lists.newArrayList(current.values());
+    }
+
+    @Override
+    public IntentState getIntentState(Key intentKey) {
+        IntentData data = current.get(intentKey);
+        return (data != null) ? data.state() : null;
+    }
+
+    @Override
+    public List<Intent> getInstallableIntents(Key intentKey) {
+        IntentData data = current.get(intentKey);
+        if (data != null) {
+            return data.installables();
+        }
+        return null;
+    }
+
+    @Override
+    public void write(IntentData newData) {
+        checkNotNull(newData);
+
+        synchronized (this) {
+            // TODO this could be refactored/cleaned up
+            IntentData currentData = current.get(newData.key());
+            IntentData pendingData = pending.get(newData.key());
+
+            if (IntentData.isUpdateAcceptable(currentData, newData)) {
+                if (pendingData != null) {
+                    if (pendingData.state() == PURGE_REQ) {
+                        current.remove(newData.key(), newData);
+                    } else {
+                        current.put(newData.key(), new IntentData(newData));
+                    }
+
+                    if (pendingData.version().compareTo(newData.version()) <= 0) {
+                        // pendingData version is less than or equal to newData's
+                        // Note: a new update for this key could be pending (it's version will be greater)
+                        pending.remove(newData.key());
+                    }
+                }
+                notifyDelegateIfNotNull(IntentEvent.getEvent(newData));
+            }
+        }
+    }
+
+    private void notifyDelegateIfNotNull(IntentEvent event) {
+        if (event != null) {
+            notifyDelegate(event);
+        }
+    }
+
+    @Override
+    public void batchWrite(Iterable<IntentData> updates) {
+        for (IntentData data : updates) {
+            write(data);
+        }
+    }
+
+    @Override
+    public Intent getIntent(Key key) {
+        IntentData data = current.get(key);
+        return (data != null) ? data.intent() : null;
+    }
+
+    @Override
+    public IntentData getIntentData(Key key) {
+        IntentData currentData = current.get(key);
+        if (currentData == null) {
+            return null;
+        }
+        return new IntentData(currentData);
+    }
+
+    @Override
+    public void addPending(IntentData data) {
+        if (data.version() == null) { // recompiled intents will already have a version
+            data.setVersion(new SystemClockTimestamp());
+        }
+        synchronized (this) {
+            IntentData existingData = pending.get(data.key());
+            if (existingData == null ||
+                    // existing version is strictly less than data's version
+                    // Note: if they are equal, we already have the update
+                    // TODO maybe we should still make this <= to be safe?
+                    existingData.version().compareTo(data.version()) < 0) {
+                pending.put(data.key(), data);
+                checkNotNull(delegate, "Store delegate is not set")
+                        .process(new IntentData(data));
+                notifyDelegateIfNotNull(IntentEvent.getEvent(data));
+            } else {
+                log.debug("IntentData {} is older than existing: {}",
+                          data, existingData);
+            }
+            //TODO consider also checking the current map at this point
+        }
+    }
+
+    @Override
+    public boolean isMaster(Key intentKey) {
+        return true;
+    }
+
+    @Override
+    public Iterable<Intent> getPending() {
+        return pending.values().stream()
+                .map(IntentData::intent)
+                .collect(Collectors.toList());
+    }
+
+    @Override
+    public Iterable<IntentData> getPendingData() {
+        return Lists.newArrayList(pending.values());
+    }
+
+    @Override
+    public Iterable<IntentData> getPendingData(boolean localOnly, long olderThan) {
+        long older = System.nanoTime() - olderThan * 1_000_000; //convert ms to ns
+        final SystemClockTimestamp time = new SystemClockTimestamp(older);
+        return pending.values().stream()
+                .filter(data -> data.version().isOlderThan(time) &&
+                        (!localOnly || isMaster(data.key())))
+                .collect(Collectors.toList());
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleLeadershipManager.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleLeadershipManager.java
new file mode 100644
index 0000000..194ffec
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleLeadershipManager.java
@@ -0,0 +1,135 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArraySet;
+import java.util.stream.Collectors;
+
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.cluster.ClusterService;
+import org.onosproject.cluster.Leadership;
+import org.onosproject.cluster.LeadershipEvent;
+import org.onosproject.cluster.LeadershipEvent.Type;
+import org.onosproject.cluster.LeadershipEventListener;
+import org.onosproject.cluster.LeadershipService;
+import org.onosproject.cluster.NodeId;
+
+/**
+ * A trivial implementation of the leadership service.
+ * <p>
+ * The service is not distributed, so it can assume there's a single leadership
+ * contender. This contender is always granted leadership whenever it asks.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleLeadershipManager implements LeadershipService {
+
+    private Set<LeadershipEventListener> listeners = new CopyOnWriteArraySet<>();
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    private ClusterService clusterService;
+
+    private Map<String, Boolean> elections = new ConcurrentHashMap<>();
+
+    @Override
+    public NodeId getLeader(String path) {
+        return elections.get(path) ? clusterService.getLocalNode().id() : null;
+    }
+
+    @Override
+    public Leadership getLeadership(String path) {
+        checkArgument(path != null);
+        return elections.get(path) ? new Leadership(path, clusterService.getLocalNode().id(), 0, 0) : null;
+    }
+
+    @Override
+    public Set<String> ownedTopics(NodeId nodeId) {
+        checkArgument(nodeId != null);
+        return elections.entrySet()
+                .stream()
+                .filter(Entry::getValue)
+                .map(Entry::getKey)
+                .collect(Collectors.toSet());
+    }
+
+    @Override
+    public CompletableFuture<Leadership> runForLeadership(String path) {
+        elections.put(path, true);
+        for (LeadershipEventListener listener : listeners) {
+            listener.event(new LeadershipEvent(Type.LEADER_ELECTED,
+                    new Leadership(path, clusterService.getLocalNode().id(), 0, 0)));
+        }
+        return CompletableFuture.completedFuture(new Leadership(path, clusterService.getLocalNode().id(), 0, 0));
+    }
+
+    @Override
+    public CompletableFuture<Void> withdraw(String path) {
+        elections.remove(path);
+        for (LeadershipEventListener listener : listeners) {
+            listener.event(new LeadershipEvent(Type.LEADER_BOOTED,
+                    new Leadership(path, clusterService.getLocalNode().id(), 0, 0)));
+        }
+        return CompletableFuture.completedFuture(null);
+    }
+
+    @Override
+    public Map<String, Leadership> getLeaderBoard() {
+        //FIXME
+        throw new UnsupportedOperationException("I don't know what to do." +
+                                                        " I wish you luck.");
+    }
+
+    @Override
+    public void addListener(LeadershipEventListener listener) {
+        listeners.add(listener);
+    }
+
+    @Override
+    public void removeListener(LeadershipEventListener listener) {
+        listeners.remove(listener);
+    }
+
+    @Override
+    public Map<String, List<NodeId>> getCandidates() {
+        return null;
+    }
+
+    @Override
+    public List<NodeId> getCandidates(String path) {
+        return null;
+    }
+
+    @Override
+    public boolean stepdown(String path) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean makeTopCandidate(String path, NodeId nodeId) {
+        throw new UnsupportedOperationException();
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkResourceStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkResourceStore.java
new file mode 100644
index 0000000..58b446c
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkResourceStore.java
@@ -0,0 +1,286 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.util.Bandwidth;
+import org.onlab.util.PositionalParameterStringFormatter;
+import org.onosproject.net.AnnotationKeys;
+import org.onosproject.net.Annotations;
+import org.onosproject.net.Link;
+import org.onosproject.net.intent.IntentId;
+import org.onosproject.net.resource.link.BandwidthResource;
+import org.onosproject.net.resource.link.BandwidthResourceAllocation;
+import org.onosproject.net.resource.link.LambdaResource;
+import org.onosproject.net.resource.link.LambdaResourceAllocation;
+import org.onosproject.net.resource.link.LinkResourceAllocations;
+import org.onosproject.net.resource.link.LinkResourceEvent;
+import org.onosproject.net.resource.link.LinkResourceStore;
+import org.onosproject.net.resource.ResourceAllocation;
+import org.onosproject.net.resource.ResourceAllocationException;
+import org.onosproject.net.resource.ResourceType;
+import org.slf4j.Logger;
+
+import com.google.common.collect.ImmutableList;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Manages link resources using trivial in-memory structures implementation.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleLinkResourceStore implements LinkResourceStore {
+    private static final BandwidthResource DEFAULT_BANDWIDTH = new BandwidthResource(Bandwidth.mbps(1_000));
+    private final Logger log = getLogger(getClass());
+
+    private Map<IntentId, LinkResourceAllocations> linkResourceAllocationsMap;
+    private Map<Link, Set<LinkResourceAllocations>> allocatedResources;
+    private Map<Link, Set<ResourceAllocation>> freeResources;
+
+    @Activate
+    public void activate() {
+        linkResourceAllocationsMap = new HashMap<>();
+        allocatedResources = new HashMap<>();
+        freeResources = new HashMap<>();
+
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        log.info("Stopped");
+    }
+
+    /**
+     * Returns free resources for a given link obtaining from topology
+     * information.
+     *
+     * @param link the target link
+     * @return free resources
+     */
+    private synchronized Set<ResourceAllocation> readOriginalFreeResources(Link link) {
+        Annotations annotations = link.annotations();
+        Set<ResourceAllocation> allocations = new HashSet<>();
+
+        try {
+            int waves = Integer.parseInt(annotations.value(AnnotationKeys.OPTICAL_WAVES));
+            for (int i = 1; i <= waves; i++) {
+                allocations.add(new LambdaResourceAllocation(LambdaResource.valueOf(i)));
+            }
+        } catch (NumberFormatException e) {
+            log.debug("No optical.wave annotation on link %s", link);
+        }
+
+        BandwidthResource bandwidth = DEFAULT_BANDWIDTH;
+        try {
+            bandwidth = new BandwidthResource(
+                    Bandwidth.mbps((Double.parseDouble(annotations.value(AnnotationKeys.BANDWIDTH)))));
+        } catch (NumberFormatException e) {
+            log.debug("No bandwidth annotation on link %s", link);
+        }
+        allocations.add(
+                new BandwidthResourceAllocation(bandwidth));
+        return allocations;
+    }
+
+    /**
+     * Finds and returns {@link BandwidthResourceAllocation} object from a given
+     * set.
+     *
+     * @param freeRes a set of ResourceAllocation object.
+     * @return {@link BandwidthResourceAllocation} object if found, otherwise
+     *         {@link BandwidthResourceAllocation} object with 0 bandwidth
+     *
+     */
+    private synchronized BandwidthResourceAllocation getBandwidth(
+            Set<ResourceAllocation> freeRes) {
+        for (ResourceAllocation res : freeRes) {
+            if (res.type() == ResourceType.BANDWIDTH) {
+                return (BandwidthResourceAllocation) res;
+            }
+        }
+        return new BandwidthResourceAllocation(new BandwidthResource(Bandwidth.bps(0)));
+    }
+
+    /**
+     * Subtracts given resources from free resources for given link.
+     *
+     * @param link the target link
+     * @param allocations the resources to be subtracted
+     */
+    private synchronized void subtractFreeResources(Link link,
+            LinkResourceAllocations allocations) {
+        // TODO Use lock or version for updating freeResources.
+        checkNotNull(link);
+        Set<ResourceAllocation> freeRes = new HashSet<>(getFreeResources(link));
+        Set<ResourceAllocation> subRes = allocations.getResourceAllocation(link);
+        for (ResourceAllocation res : subRes) {
+            switch (res.type()) {
+            case BANDWIDTH:
+                BandwidthResourceAllocation ba = getBandwidth(freeRes);
+                double requestedBandwidth =
+                        ((BandwidthResourceAllocation) res).bandwidth().toDouble();
+                double newBandwidth = ba.bandwidth().toDouble() - requestedBandwidth;
+                if (newBandwidth < 0.0) {
+                    throw new ResourceAllocationException(
+                            PositionalParameterStringFormatter.format(
+                            "Unable to allocate bandwidth for link {} "
+                            + "requested amount is {} current allocation is {}",
+                                    link,
+                                    requestedBandwidth,
+                                    ba));
+                }
+                freeRes.remove(ba);
+                freeRes.add(new BandwidthResourceAllocation(
+                        new BandwidthResource(Bandwidth.bps(newBandwidth))));
+                break;
+            case LAMBDA:
+                final boolean lambdaAvailable = freeRes.remove(res);
+                if (!lambdaAvailable) {
+                    int requestedLambda =
+                            ((LambdaResourceAllocation) res).lambda().toInt();
+                    throw new ResourceAllocationException(
+                            PositionalParameterStringFormatter.format(
+                                    "Unable to allocate lambda for link {} lambda is {}",
+                                    link,
+                                    requestedLambda));
+                }
+                break;
+            default:
+                break;
+            }
+        }
+        freeResources.put(link, freeRes);
+
+    }
+
+    /**
+     * Adds given resources to free resources for given link.
+     *
+     * @param link the target link
+     * @param allocations the resources to be added
+     */
+    private synchronized void addFreeResources(Link link,
+            LinkResourceAllocations allocations) {
+        // TODO Use lock or version for updating freeResources.
+        Set<ResourceAllocation> freeRes = new HashSet<>(getFreeResources(link));
+        Set<ResourceAllocation> addRes = allocations.getResourceAllocation(link);
+        for (ResourceAllocation res : addRes) {
+            switch (res.type()) {
+            case BANDWIDTH:
+                BandwidthResourceAllocation ba = getBandwidth(freeRes);
+                double requestedBandwidth =
+                        ((BandwidthResourceAllocation) res).bandwidth().toDouble();
+                double newBandwidth = ba.bandwidth().toDouble() + requestedBandwidth;
+                freeRes.remove(ba);
+                freeRes.add(new BandwidthResourceAllocation(
+                        new BandwidthResource(Bandwidth.bps(newBandwidth))));
+                break;
+            case LAMBDA:
+                checkState(freeRes.add(res));
+                break;
+            default:
+                break;
+            }
+        }
+        freeResources.put(link, freeRes);
+    }
+
+    @Override
+    public synchronized Set<ResourceAllocation> getFreeResources(Link link) {
+        checkNotNull(link);
+        Set<ResourceAllocation> freeRes = freeResources.get(link);
+        if (freeRes == null) {
+            freeRes = readOriginalFreeResources(link);
+        }
+
+        return freeRes;
+    }
+
+    @Override
+    public synchronized void allocateResources(LinkResourceAllocations allocations) {
+        checkNotNull(allocations);
+        linkResourceAllocationsMap.put(allocations.intentId(), allocations);
+        for (Link link : allocations.links()) {
+            subtractFreeResources(link, allocations);
+            Set<LinkResourceAllocations> linkAllocs = allocatedResources.get(link);
+            if (linkAllocs == null) {
+                linkAllocs = new HashSet<>();
+            }
+            linkAllocs.add(allocations);
+            allocatedResources.put(link, linkAllocs);
+        }
+    }
+
+    @Override
+    public synchronized LinkResourceEvent releaseResources(LinkResourceAllocations allocations) {
+        checkNotNull(allocations);
+        linkResourceAllocationsMap.remove(allocations.intentId());
+        for (Link link : allocations.links()) {
+            addFreeResources(link, allocations);
+            Set<LinkResourceAllocations> linkAllocs = allocatedResources.get(link);
+            if (linkAllocs == null) {
+                log.error("Missing resource allocation.");
+            } else {
+                linkAllocs.remove(allocations);
+            }
+            allocatedResources.put(link, linkAllocs);
+        }
+
+        final List<LinkResourceAllocations> releasedResources =
+                ImmutableList.of(allocations);
+
+        return new LinkResourceEvent(
+                LinkResourceEvent.Type.ADDITIONAL_RESOURCES_AVAILABLE,
+                releasedResources);
+    }
+
+    @Override
+    public synchronized LinkResourceAllocations getAllocations(IntentId intentId) {
+        checkNotNull(intentId);
+        return linkResourceAllocationsMap.get(intentId);
+    }
+
+    @Override
+    public synchronized Iterable<LinkResourceAllocations> getAllocations(Link link) {
+        checkNotNull(link);
+        Set<LinkResourceAllocations> result = allocatedResources.get(link);
+        if (result == null) {
+            result = Collections.emptySet();
+        }
+        return Collections.unmodifiableSet(result);
+    }
+
+    @Override
+    public synchronized Iterable<LinkResourceAllocations> getAllocations() {
+        return Collections.unmodifiableCollection(linkResourceAllocationsMap.values());
+    }
+
+
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkResourceStoreTest.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkResourceStoreTest.java
new file mode 100644
index 0000000..238e75d
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkResourceStoreTest.java
@@ -0,0 +1,307 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.util.Bandwidth;
+import org.onosproject.net.AnnotationKeys;
+import org.onosproject.net.Annotations;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DefaultAnnotations;
+import org.onosproject.net.DefaultLink;
+import org.onosproject.net.Link;
+import org.onosproject.net.intent.IntentId;
+import org.onosproject.net.provider.ProviderId;
+import org.onosproject.net.resource.link.BandwidthResource;
+import org.onosproject.net.resource.link.BandwidthResourceAllocation;
+import org.onosproject.net.resource.link.LambdaResource;
+import org.onosproject.net.resource.link.LambdaResourceAllocation;
+import org.onosproject.net.resource.link.LinkResourceAllocations;
+import org.onosproject.net.resource.link.LinkResourceStore;
+import org.onosproject.net.resource.ResourceAllocation;
+import org.onosproject.net.resource.ResourceAllocationException;
+import org.onosproject.net.resource.ResourceRequest;
+import org.onosproject.net.resource.ResourceType;
+
+import com.google.common.collect.ImmutableSet;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.onosproject.net.DeviceId.deviceId;
+import static org.onosproject.net.Link.Type.DIRECT;
+import static org.onosproject.net.PortNumber.portNumber;
+
+/**
+ * Test of the simple LinkResourceStore implementation.
+ */
+public class SimpleLinkResourceStoreTest {
+
+    private LinkResourceStore store;
+    private SimpleLinkResourceStore simpleStore;
+    private Link link1;
+    private Link link2;
+    private Link link3;
+
+    /**
+     * Returns {@link Link} object.
+     *
+     * @param dev1 source device
+     * @param port1 source port
+     * @param dev2 destination device
+     * @param port2 destination port
+     * @return created {@link Link} object
+     */
+    private static Link newLink(String dev1, int port1, String dev2, int port2) {
+        Annotations annotations = DefaultAnnotations.builder()
+                .set(AnnotationKeys.OPTICAL_WAVES, "80")
+                .set(AnnotationKeys.BANDWIDTH, "1000")
+                .build();
+        return new DefaultLink(
+                new ProviderId("of", "foo"),
+                new ConnectPoint(deviceId(dev1), portNumber(port1)),
+                new ConnectPoint(deviceId(dev2), portNumber(port2)),
+                DIRECT, annotations);
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        simpleStore = new SimpleLinkResourceStore();
+        simpleStore.activate();
+        store = simpleStore;
+
+        link1 = newLink("of:1", 1, "of:2", 2);
+        link2 = newLink("of:2", 1, "of:3", 2);
+        link3 = newLink("of:3", 1, "of:4", 2);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        simpleStore.deactivate();
+    }
+
+    /**
+     * Tests constructor and activate method.
+     */
+    @Test
+    public void testConstructorAndActivate() {
+        final Iterable<LinkResourceAllocations> allAllocations = store.getAllocations();
+        assertNotNull(allAllocations);
+        assertFalse(allAllocations.iterator().hasNext());
+
+        final Iterable<LinkResourceAllocations> linkAllocations =
+                store.getAllocations(link1);
+        assertNotNull(linkAllocations);
+        assertFalse(linkAllocations.iterator().hasNext());
+
+        final Set<ResourceAllocation> res = store.getFreeResources(link2);
+        assertNotNull(res);
+    }
+
+    /**
+     * Picks up and returns one of bandwidth allocations from a given set.
+     *
+     * @param resources the set of {@link ResourceAllocation}s
+     * @return {@link BandwidthResourceAllocation} object if found, null
+     *         otherwise
+     */
+    private BandwidthResourceAllocation getBandwidthObj(Set<ResourceAllocation> resources) {
+        for (ResourceAllocation res : resources) {
+            if (res.type() == ResourceType.BANDWIDTH) {
+                return ((BandwidthResourceAllocation) res);
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Returns all lambda allocations from a given set.
+     *
+     * @param resources the set of {@link ResourceAllocation}s
+     * @return a set of {@link LambdaResourceAllocation} objects
+     */
+    private Set<LambdaResourceAllocation> getLambdaObjs(Set<ResourceAllocation> resources) {
+        Set<LambdaResourceAllocation> lambdaResources = new HashSet<>();
+        for (ResourceAllocation res : resources) {
+            if (res.type() == ResourceType.LAMBDA) {
+                lambdaResources.add((LambdaResourceAllocation) res);
+            }
+        }
+        return lambdaResources;
+    }
+
+    /**
+     * Tests initial free bandwidth for a link.
+     */
+    @Test
+    public void testInitialBandwidth() {
+        final Set<ResourceAllocation> freeRes = store.getFreeResources(link1);
+        assertNotNull(freeRes);
+
+        final BandwidthResourceAllocation alloc = getBandwidthObj(freeRes);
+        assertNotNull(alloc);
+
+        assertEquals(new BandwidthResource(Bandwidth.mbps(1000.0)), alloc.bandwidth());
+    }
+
+    /**
+     * Tests initial free lambda for a link.
+     */
+    @Test
+    public void testInitialLambdas() {
+        final Set<ResourceAllocation> freeRes = store.getFreeResources(link3);
+        assertNotNull(freeRes);
+
+        final Set<LambdaResourceAllocation> res = getLambdaObjs(freeRes);
+        assertNotNull(res);
+        assertEquals(80, res.size());
+    }
+
+    public static class MockLinkResourceBandwidthAllocations implements LinkResourceAllocations {
+        final double allocationAmount;
+
+        MockLinkResourceBandwidthAllocations(Double allocationAmount) {
+            this.allocationAmount = allocationAmount;
+        }
+        @Override
+        public Set<ResourceAllocation> getResourceAllocation(Link link) {
+            final ResourceAllocation allocation =
+                    new BandwidthResourceAllocation(new BandwidthResource(Bandwidth.bps(allocationAmount)));
+            final Set<ResourceAllocation> allocations = new HashSet<>();
+            allocations.add(allocation);
+            return allocations;
+        }
+
+        @Override
+        public IntentId intentId() {
+            return null;
+        }
+
+        @Override
+        public Collection<Link> links() {
+            return ImmutableSet.of(newLink("of:1", 1, "of:2", 2));
+        }
+
+        @Override
+        public Set<ResourceRequest> resources() {
+            return null;
+        }
+
+        @Override
+        public ResourceType type() {
+            return null;
+        }
+    }
+
+    public static class MockLinkResourceLambdaAllocations implements LinkResourceAllocations {
+        final int allocatedLambda;
+
+        MockLinkResourceLambdaAllocations(int allocatedLambda) {
+            this.allocatedLambda = allocatedLambda;
+        }
+        @Override
+        public Set<ResourceAllocation> getResourceAllocation(Link link) {
+            final ResourceAllocation allocation =
+                    new LambdaResourceAllocation(LambdaResource.valueOf(allocatedLambda));
+            final Set<ResourceAllocation> allocations = new HashSet<>();
+            allocations.add(allocation);
+            return allocations;
+        }
+
+        @Override
+        public IntentId intentId() {
+            return null;
+        }
+
+        @Override
+        public Collection<Link> links() {
+            return ImmutableSet.of(newLink("of:1", 1, "of:2", 2));
+        }
+
+        @Override
+        public Set<ResourceRequest> resources() {
+            return null;
+        }
+
+        @Override
+        public ResourceType type() {
+            return null;
+        }
+    }
+
+    /**
+     * Tests a successful bandwidth allocation.
+     */
+    @Test
+    public void testSuccessfulBandwidthAllocation() {
+        final LinkResourceAllocations allocations =
+                new MockLinkResourceBandwidthAllocations(900.0);
+        store.allocateResources(allocations);
+    }
+
+    /**
+     * Tests an unsuccessful bandwidth allocation.
+     */
+    @Test
+    public void testUnsuccessfulBandwidthAllocation() {
+        final LinkResourceAllocations allocations =
+                new MockLinkResourceBandwidthAllocations(2000000000.0);
+        boolean gotException = false;
+        try {
+            store.allocateResources(allocations);
+        } catch (ResourceAllocationException rae) {
+            assertEquals(true, rae.getMessage().contains("Unable to allocate bandwidth for link"));
+            gotException = true;
+        }
+        assertEquals(true, gotException);
+    }
+
+    /**
+     * Tests a successful lambda allocation.
+     */
+    @Test
+    public void testSuccessfulLambdaAllocation() {
+        final LinkResourceAllocations allocations =
+                new MockLinkResourceLambdaAllocations(1);
+        store.allocateResources(allocations);
+    }
+
+    /**
+     * Tests an unsuccessful lambda allocation.
+     */
+    @Test
+    public void testUnsuccessfulLambdaAllocation() {
+        final LinkResourceAllocations allocations =
+                new MockLinkResourceLambdaAllocations(1);
+        store.allocateResources(allocations);
+
+        boolean gotException = false;
+
+        try {
+            store.allocateResources(allocations);
+        } catch (ResourceAllocationException rae) {
+            assertEquals(true, rae.getMessage().contains("Unable to allocate lambda for link"));
+            gotException = true;
+        }
+        assertEquals(true, gotException);
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkStore.java
new file mode 100644
index 0000000..d0be2b1
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkStore.java
@@ -0,0 +1,366 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.base.Function;
+import com.google.common.collect.FluentIterable;
+import com.google.common.collect.Multimaps;
+import com.google.common.collect.SetMultimap;
+import com.google.common.collect.Sets;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.net.AnnotationKeys;
+import org.onosproject.net.AnnotationsUtil;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DefaultAnnotations;
+import org.onosproject.net.DefaultLink;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Link;
+import org.onosproject.net.Link.Type;
+import org.onosproject.net.LinkKey;
+import org.onosproject.net.SparseAnnotations;
+import org.onosproject.net.link.DefaultLinkDescription;
+import org.onosproject.net.link.LinkDescription;
+import org.onosproject.net.link.LinkEvent;
+import org.onosproject.net.link.LinkStore;
+import org.onosproject.net.link.LinkStoreDelegate;
+import org.onosproject.net.provider.ProviderId;
+import org.onosproject.store.AbstractStore;
+import org.slf4j.Logger;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+import static com.google.common.base.Predicates.notNull;
+import static com.google.common.base.Verify.verifyNotNull;
+import static com.google.common.collect.Multimaps.synchronizedSetMultimap;
+import static org.onosproject.net.DefaultAnnotations.merge;
+import static org.onosproject.net.DefaultAnnotations.union;
+import static org.onosproject.net.Link.State.ACTIVE;
+import static org.onosproject.net.Link.State.INACTIVE;
+import static org.onosproject.net.Link.Type.DIRECT;
+import static org.onosproject.net.Link.Type.INDIRECT;
+import static org.onosproject.net.LinkKey.linkKey;
+import static org.onosproject.net.link.LinkEvent.Type.*;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Manages inventory of infrastructure links using trivial in-memory structures
+ * implementation.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleLinkStore
+        extends AbstractStore<LinkEvent, LinkStoreDelegate>
+        implements LinkStore {
+
+    private final Logger log = getLogger(getClass());
+
+    // Link inventory
+    private final ConcurrentMap<LinkKey, Map<ProviderId, LinkDescription>>
+            linkDescs = new ConcurrentHashMap<>();
+
+    // Link instance cache
+    private final ConcurrentMap<LinkKey, Link> links = new ConcurrentHashMap<>();
+
+    // Egress and ingress link sets
+    private final SetMultimap<DeviceId, LinkKey> srcLinks = createSynchronizedHashMultiMap();
+    private final SetMultimap<DeviceId, LinkKey> dstLinks = createSynchronizedHashMultiMap();
+
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        linkDescs.clear();
+        links.clear();
+        srcLinks.clear();
+        dstLinks.clear();
+        log.info("Stopped");
+    }
+
+    @Override
+    public int getLinkCount() {
+        return links.size();
+    }
+
+    @Override
+    public Iterable<Link> getLinks() {
+        return Collections.unmodifiableCollection(links.values());
+    }
+
+    @Override
+    public Set<Link> getDeviceEgressLinks(DeviceId deviceId) {
+        // lock for iteration
+        synchronized (srcLinks) {
+            return FluentIterable.from(srcLinks.get(deviceId))
+                    .transform(lookupLink())
+                    .filter(notNull())
+                    .toSet();
+        }
+    }
+
+    @Override
+    public Set<Link> getDeviceIngressLinks(DeviceId deviceId) {
+        // lock for iteration
+        synchronized (dstLinks) {
+            return FluentIterable.from(dstLinks.get(deviceId))
+                    .transform(lookupLink())
+                    .filter(notNull())
+                    .toSet();
+        }
+    }
+
+    @Override
+    public Link getLink(ConnectPoint src, ConnectPoint dst) {
+        return links.get(linkKey(src, dst));
+    }
+
+    @Override
+    public Set<Link> getEgressLinks(ConnectPoint src) {
+        Set<Link> egress = new HashSet<>();
+        synchronized (srcLinks) {
+            for (LinkKey linkKey : srcLinks.get(src.deviceId())) {
+                if (linkKey.src().equals(src)) {
+                    egress.add(links.get(linkKey));
+                }
+            }
+        }
+        return egress;
+    }
+
+    @Override
+    public Set<Link> getIngressLinks(ConnectPoint dst) {
+        Set<Link> ingress = new HashSet<>();
+        synchronized (dstLinks) {
+            for (LinkKey linkKey : dstLinks.get(dst.deviceId())) {
+                if (linkKey.dst().equals(dst)) {
+                    ingress.add(links.get(linkKey));
+                }
+            }
+        }
+        return ingress;
+    }
+
+    @Override
+    public LinkEvent createOrUpdateLink(ProviderId providerId,
+                                        LinkDescription linkDescription) {
+        LinkKey key = linkKey(linkDescription.src(), linkDescription.dst());
+
+        Map<ProviderId, LinkDescription> descs = getOrCreateLinkDescriptions(key);
+        synchronized (descs) {
+            final Link oldLink = links.get(key);
+            // update description
+            createOrUpdateLinkDescription(descs, providerId, linkDescription);
+            final Link newLink = composeLink(descs);
+            if (oldLink == null) {
+                return createLink(key, newLink);
+            }
+            return updateLink(key, oldLink, newLink);
+        }
+    }
+
+    @Override
+    public LinkEvent removeOrDownLink(ConnectPoint src, ConnectPoint dst) {
+        Link link = getLink(src, dst);
+        if (link == null) {
+            return null;
+        }
+
+        if (link.isDurable()) {
+            return link.state() == INACTIVE ? null :
+                    updateLink(linkKey(link.src(), link.dst()), link,
+                               new DefaultLink(link.providerId(),
+                                               link.src(), link.dst(),
+                                               link.type(), INACTIVE,
+                                               link.isDurable(),
+                                               link.annotations()));
+        }
+        return removeLink(src, dst);
+    }
+
+    // Guarded by linkDescs value (=locking each Link)
+    private LinkDescription createOrUpdateLinkDescription(
+            Map<ProviderId, LinkDescription> descs,
+            ProviderId providerId,
+            LinkDescription linkDescription) {
+
+        // merge existing attributes and merge
+        LinkDescription oldDesc = descs.get(providerId);
+        LinkDescription newDesc = linkDescription;
+        if (oldDesc != null) {
+            // we only allow transition from INDIRECT -> DIRECT
+            final Type newType;
+            if (oldDesc.type() == DIRECT) {
+                newType = DIRECT;
+            } else {
+                newType = linkDescription.type();
+            }
+            SparseAnnotations merged = union(oldDesc.annotations(),
+                                             linkDescription.annotations());
+            newDesc = new DefaultLinkDescription(linkDescription.src(),
+                                                 linkDescription.dst(),
+                                                 newType, merged);
+        }
+        return descs.put(providerId, newDesc);
+    }
+
+    // Creates and stores the link and returns the appropriate event.
+    // Guarded by linkDescs value (=locking each Link)
+    private LinkEvent createLink(LinkKey key, Link newLink) {
+        links.put(key, newLink);
+        srcLinks.put(newLink.src().deviceId(), key);
+        dstLinks.put(newLink.dst().deviceId(), key);
+        return new LinkEvent(LINK_ADDED, newLink);
+    }
+
+    // Updates, if necessary the specified link and returns the appropriate event.
+    // Guarded by linkDescs value (=locking each Link)
+    private LinkEvent updateLink(LinkKey key, Link oldLink, Link newLink) {
+        if (oldLink.state() != newLink.state() ||
+                (oldLink.type() == INDIRECT && newLink.type() == DIRECT) ||
+                !AnnotationsUtil.isEqual(oldLink.annotations(), newLink.annotations())) {
+
+            links.put(key, newLink);
+            // strictly speaking following can be ommitted
+            srcLinks.put(oldLink.src().deviceId(), key);
+            dstLinks.put(oldLink.dst().deviceId(), key);
+            return new LinkEvent(LINK_UPDATED, newLink);
+        }
+        return null;
+    }
+
+    @Override
+    public LinkEvent removeLink(ConnectPoint src, ConnectPoint dst) {
+        final LinkKey key = linkKey(src, dst);
+        Map<ProviderId, LinkDescription> descs = getOrCreateLinkDescriptions(key);
+        synchronized (descs) {
+            Link link = links.remove(key);
+            descs.clear();
+            if (link != null) {
+                srcLinks.remove(link.src().deviceId(), key);
+                dstLinks.remove(link.dst().deviceId(), key);
+                return new LinkEvent(LINK_REMOVED, link);
+            }
+            return null;
+        }
+    }
+
+    /**
+     * Creates concurrent readable, synchronized HashMultimap.
+     *
+     * @return SetMultimap
+     */
+    private static <K, V> SetMultimap<K, V> createSynchronizedHashMultiMap() {
+        return synchronizedSetMultimap(
+               Multimaps.newSetMultimap(new ConcurrentHashMap<K, Collection<V>>(),
+                                       () -> Sets.newConcurrentHashSet()));
+    }
+
+    /**
+     * @return primary ProviderID, or randomly chosen one if none exists
+     */
+    // Guarded by linkDescs value (=locking each Link)
+    private ProviderId getBaseProviderId(Map<ProviderId, LinkDescription> providerDescs) {
+
+        ProviderId fallBackPrimary = null;
+        for (Entry<ProviderId, LinkDescription> e : providerDescs.entrySet()) {
+            if (!e.getKey().isAncillary()) {
+                return e.getKey();
+            } else if (fallBackPrimary == null) {
+                // pick randomly as a fallback in case there is no primary
+                fallBackPrimary = e.getKey();
+            }
+        }
+        return fallBackPrimary;
+    }
+
+    // Guarded by linkDescs value (=locking each Link)
+    private Link composeLink(Map<ProviderId, LinkDescription> descs) {
+        ProviderId primary = getBaseProviderId(descs);
+        LinkDescription base = descs.get(verifyNotNull(primary));
+
+        ConnectPoint src = base.src();
+        ConnectPoint dst = base.dst();
+        Type type = base.type();
+        DefaultAnnotations annotations = DefaultAnnotations.builder().build();
+        annotations = merge(annotations, base.annotations());
+
+        for (Entry<ProviderId, LinkDescription> e : descs.entrySet()) {
+            if (primary.equals(e.getKey())) {
+                continue;
+            }
+
+            // TODO: should keep track of Description timestamp
+            // and only merge conflicting keys when timestamp is newer
+            // Currently assuming there will never be a key conflict between
+            // providers
+
+            // annotation merging. not so efficient, should revisit later
+            annotations = merge(annotations, e.getValue().annotations());
+        }
+
+        boolean isDurable = Objects.equals(annotations.value(AnnotationKeys.DURABLE), "true");
+        return new DefaultLink(primary, src, dst, type, ACTIVE, isDurable, annotations);
+    }
+
+    private Map<ProviderId, LinkDescription> getOrCreateLinkDescriptions(LinkKey key) {
+        Map<ProviderId, LinkDescription> r;
+        r = linkDescs.get(key);
+        if (r != null) {
+            return r;
+        }
+        r = new HashMap<>();
+        final Map<ProviderId, LinkDescription> concurrentlyAdded;
+        concurrentlyAdded = linkDescs.putIfAbsent(key, r);
+        if (concurrentlyAdded == null) {
+            return r;
+        } else {
+            return concurrentlyAdded;
+        }
+    }
+
+    private final Function<LinkKey, Link> lookupLink = new LookupLink();
+
+    private Function<LinkKey, Link> lookupLink() {
+        return lookupLink;
+    }
+
+    private final class LookupLink implements Function<LinkKey, Link> {
+        @Override
+        public Link apply(LinkKey input) {
+            if (input == null) {
+                return null;
+            } else {
+                return links.get(input);
+            }
+        }
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkStoreTest.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkStoreTest.java
new file mode 100644
index 0000000..2d2b275
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleLinkStoreTest.java
@@ -0,0 +1,542 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.collect.Iterables;
+
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.onosproject.net.AnnotationKeys;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DefaultAnnotations;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Link;
+import org.onosproject.net.Link.Type;
+import org.onosproject.net.LinkKey;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.SparseAnnotations;
+import org.onosproject.net.link.DefaultLinkDescription;
+import org.onosproject.net.link.LinkEvent;
+import org.onosproject.net.link.LinkStore;
+import org.onosproject.net.link.LinkStoreDelegate;
+import org.onosproject.net.provider.ProviderId;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.Assert.*;
+import static org.onosproject.net.DeviceId.deviceId;
+import static org.onosproject.net.Link.Type.*;
+import static org.onosproject.net.link.LinkEvent.Type.*;
+import static org.onosproject.net.NetTestTools.assertAnnotationsEquals;
+
+/**
+ * Test of the simple LinkStore implementation.
+ */
+public class SimpleLinkStoreTest {
+
+    private static final ProviderId PID = new ProviderId("of", "foo");
+    private static final ProviderId PIDA = new ProviderId("of", "bar", true);
+    private static final DeviceId DID1 = deviceId("of:foo");
+    private static final DeviceId DID2 = deviceId("of:bar");
+
+    private static final PortNumber P1 = PortNumber.portNumber(1);
+    private static final PortNumber P2 = PortNumber.portNumber(2);
+    private static final PortNumber P3 = PortNumber.portNumber(3);
+
+    private static final SparseAnnotations A1 = DefaultAnnotations.builder()
+            .set("A1", "a1")
+            .set("B1", "b1")
+            .build();
+    private static final SparseAnnotations A1_2 = DefaultAnnotations.builder()
+            .remove("A1")
+            .set("B3", "b3")
+            .build();
+    private static final SparseAnnotations A2 = DefaultAnnotations.builder()
+            .set("A2", "a2")
+            .set("B2", "b2")
+            .build();
+    private static final SparseAnnotations A2_2 = DefaultAnnotations.builder()
+            .remove("A2")
+            .set("B4", "b4")
+            .build();
+
+    private static final SparseAnnotations DA1 = DefaultAnnotations.builder()
+            .set("A1", "a1")
+            .set("B1", "b1")
+            .set(AnnotationKeys.DURABLE, "true")
+            .build();
+    private static final SparseAnnotations DA2 = DefaultAnnotations.builder()
+            .set("A2", "a2")
+            .set("B2", "b2")
+            .set(AnnotationKeys.DURABLE, "true")
+            .build();
+    private static final SparseAnnotations NDA1 = DefaultAnnotations.builder()
+            .set("A1", "a1")
+            .set("B1", "b1")
+            .remove(AnnotationKeys.DURABLE)
+            .build();
+
+
+
+    private SimpleLinkStore simpleLinkStore;
+    private LinkStore linkStore;
+
+    @BeforeClass
+    public static void setUpBeforeClass() throws Exception {
+    }
+
+    @AfterClass
+    public static void tearDownAfterClass() throws Exception {
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        simpleLinkStore = new SimpleLinkStore();
+        simpleLinkStore.activate();
+        linkStore = simpleLinkStore;
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        simpleLinkStore.deactivate();
+    }
+
+    private void putLink(DeviceId srcId, PortNumber srcNum,
+                         DeviceId dstId, PortNumber dstNum,
+                         Type type, boolean isDurable,
+                         SparseAnnotations... annotations) {
+        ConnectPoint src = new ConnectPoint(srcId, srcNum);
+        ConnectPoint dst = new ConnectPoint(dstId, dstNum);
+        linkStore.createOrUpdateLink(PID, new DefaultLinkDescription(src, dst, type,
+                                                                     annotations));
+    }
+
+    private void putLink(LinkKey key, Type type, SparseAnnotations... annotations) {
+        putLink(key.src().deviceId(), key.src().port(),
+                key.dst().deviceId(), key.dst().port(),
+                type, false, annotations);
+    }
+
+    private static void assertLink(DeviceId srcId, PortNumber srcNum,
+                            DeviceId dstId, PortNumber dstNum, Type type,
+                            Link link) {
+        assertEquals(srcId, link.src().deviceId());
+        assertEquals(srcNum, link.src().port());
+        assertEquals(dstId, link.dst().deviceId());
+        assertEquals(dstNum, link.dst().port());
+        assertEquals(type, link.type());
+    }
+
+    private static void assertLink(LinkKey key, Type type, Link link) {
+        assertLink(key.src().deviceId(), key.src().port(),
+                   key.dst().deviceId(), key.dst().port(),
+                   type, link);
+    }
+
+    @Test
+    public final void testGetLinkCount() {
+        assertEquals("initialy empty", 0, linkStore.getLinkCount());
+
+        putLink(DID1, P1, DID2, P2, DIRECT, false);
+        putLink(DID2, P2, DID1, P1, DIRECT, false);
+        putLink(DID1, P1, DID2, P2, DIRECT, false);
+
+        assertEquals("expecting 2 unique link", 2, linkStore.getLinkCount());
+    }
+
+    @Test
+    public final void testGetLinks() {
+        assertEquals("initialy empty", 0,
+                Iterables.size(linkStore.getLinks()));
+
+        LinkKey linkId1 = LinkKey.linkKey(new ConnectPoint(DID1, P1), new ConnectPoint(DID2, P2));
+        LinkKey linkId2 = LinkKey.linkKey(new ConnectPoint(DID2, P2), new ConnectPoint(DID1, P1));
+
+        putLink(linkId1, DIRECT);
+        putLink(linkId2, DIRECT);
+        putLink(linkId1, DIRECT);
+
+        assertEquals("expecting 2 unique link", 2,
+                Iterables.size(linkStore.getLinks()));
+
+        Map<LinkKey, Link> links = new HashMap<>();
+        for (Link link : linkStore.getLinks()) {
+            links.put(LinkKey.linkKey(link), link);
+        }
+
+        assertLink(linkId1, DIRECT, links.get(linkId1));
+        assertLink(linkId2, DIRECT, links.get(linkId2));
+    }
+
+    @Test
+    public final void testGetDeviceEgressLinks() {
+        LinkKey linkId1 = LinkKey.linkKey(new ConnectPoint(DID1, P1), new ConnectPoint(DID2, P2));
+        LinkKey linkId2 = LinkKey.linkKey(new ConnectPoint(DID2, P2), new ConnectPoint(DID1, P1));
+        LinkKey linkId3 = LinkKey.linkKey(new ConnectPoint(DID1, P2), new ConnectPoint(DID2, P3));
+
+        putLink(linkId1, DIRECT);
+        putLink(linkId2, DIRECT);
+        putLink(linkId3, DIRECT);
+
+        // DID1,P1 => DID2,P2
+        // DID2,P2 => DID1,P1
+        // DID1,P2 => DID2,P3
+
+        Set<Link> links1 = linkStore.getDeviceEgressLinks(DID1);
+        assertEquals(2, links1.size());
+        // check
+
+        Set<Link> links2 = linkStore.getDeviceEgressLinks(DID2);
+        assertEquals(1, links2.size());
+        assertLink(linkId2, DIRECT, links2.iterator().next());
+    }
+
+    @Test
+    public final void testGetDeviceIngressLinks() {
+        LinkKey linkId1 = LinkKey.linkKey(new ConnectPoint(DID1, P1), new ConnectPoint(DID2, P2));
+        LinkKey linkId2 = LinkKey.linkKey(new ConnectPoint(DID2, P2), new ConnectPoint(DID1, P1));
+        LinkKey linkId3 = LinkKey.linkKey(new ConnectPoint(DID1, P2), new ConnectPoint(DID2, P3));
+
+        putLink(linkId1, DIRECT);
+        putLink(linkId2, DIRECT);
+        putLink(linkId3, DIRECT);
+
+        // DID1,P1 => DID2,P2
+        // DID2,P2 => DID1,P1
+        // DID1,P2 => DID2,P3
+
+        Set<Link> links1 = linkStore.getDeviceIngressLinks(DID2);
+        assertEquals(2, links1.size());
+        // check
+
+        Set<Link> links2 = linkStore.getDeviceIngressLinks(DID1);
+        assertEquals(1, links2.size());
+        assertLink(linkId2, DIRECT, links2.iterator().next());
+    }
+
+    @Test
+    public final void testGetLink() {
+        ConnectPoint src = new ConnectPoint(DID1, P1);
+        ConnectPoint dst = new ConnectPoint(DID2, P2);
+        LinkKey linkId1 = LinkKey.linkKey(src, dst);
+
+        putLink(linkId1, DIRECT);
+
+        Link link = linkStore.getLink(src, dst);
+        assertLink(linkId1, DIRECT, link);
+
+        assertNull("There shouldn't be reverese link",
+                linkStore.getLink(dst, src));
+    }
+
+    @Test
+    public final void testGetEgressLinks() {
+        final ConnectPoint d1P1 = new ConnectPoint(DID1, P1);
+        final ConnectPoint d2P2 = new ConnectPoint(DID2, P2);
+        LinkKey linkId1 = LinkKey.linkKey(d1P1, d2P2);
+        LinkKey linkId2 = LinkKey.linkKey(d2P2, d1P1);
+        LinkKey linkId3 = LinkKey.linkKey(new ConnectPoint(DID1, P2), new ConnectPoint(DID2, P3));
+
+        putLink(linkId1, DIRECT);
+        putLink(linkId2, DIRECT);
+        putLink(linkId3, DIRECT);
+
+        // DID1,P1 => DID2,P2
+        // DID2,P2 => DID1,P1
+        // DID1,P2 => DID2,P3
+
+        Set<Link> links1 = linkStore.getEgressLinks(d1P1);
+        assertEquals(1, links1.size());
+        assertLink(linkId1, DIRECT, links1.iterator().next());
+
+        Set<Link> links2 = linkStore.getEgressLinks(d2P2);
+        assertEquals(1, links2.size());
+        assertLink(linkId2, DIRECT, links2.iterator().next());
+    }
+
+    @Test
+    public final void testGetIngressLinks() {
+        final ConnectPoint d1P1 = new ConnectPoint(DID1, P1);
+        final ConnectPoint d2P2 = new ConnectPoint(DID2, P2);
+        LinkKey linkId1 = LinkKey.linkKey(d1P1, d2P2);
+        LinkKey linkId2 = LinkKey.linkKey(d2P2, d1P1);
+        LinkKey linkId3 = LinkKey.linkKey(new ConnectPoint(DID1, P2), new ConnectPoint(DID2, P3));
+
+        putLink(linkId1, DIRECT);
+        putLink(linkId2, DIRECT);
+        putLink(linkId3, DIRECT);
+
+        // DID1,P1 => DID2,P2
+        // DID2,P2 => DID1,P1
+        // DID1,P2 => DID2,P3
+
+        Set<Link> links1 = linkStore.getIngressLinks(d2P2);
+        assertEquals(1, links1.size());
+        assertLink(linkId1, DIRECT, links1.iterator().next());
+
+        Set<Link> links2 = linkStore.getIngressLinks(d1P1);
+        assertEquals(1, links2.size());
+        assertLink(linkId2, DIRECT, links2.iterator().next());
+    }
+
+    @Test
+    public final void testCreateOrUpdateLink() {
+        ConnectPoint src = new ConnectPoint(DID1, P1);
+        ConnectPoint dst = new ConnectPoint(DID2, P2);
+
+        // add link
+        LinkEvent event = linkStore.createOrUpdateLink(PID,
+                    new DefaultLinkDescription(src, dst, INDIRECT));
+
+        assertLink(DID1, P1, DID2, P2, INDIRECT, event.subject());
+        assertEquals(LINK_ADDED, event.type());
+
+        // update link type
+        LinkEvent event2 = linkStore.createOrUpdateLink(PID,
+                new DefaultLinkDescription(src, dst, DIRECT));
+
+        assertLink(DID1, P1, DID2, P2, DIRECT, event2.subject());
+        assertEquals(LINK_UPDATED, event2.type());
+
+        // no change
+        LinkEvent event3 = linkStore.createOrUpdateLink(PID,
+                new DefaultLinkDescription(src, dst, DIRECT));
+
+        assertNull("No change event expected", event3);
+    }
+
+    @Test
+    public final void testCreateOrUpdateLinkAncillary() {
+        ConnectPoint src = new ConnectPoint(DID1, P1);
+        ConnectPoint dst = new ConnectPoint(DID2, P2);
+
+        // add Ancillary link
+        LinkEvent event = linkStore.createOrUpdateLink(PIDA,
+                    new DefaultLinkDescription(src, dst, INDIRECT, A1));
+
+        assertNotNull("Ancillary only link is ignored", event);
+
+        // add Primary link
+        LinkEvent event2 = linkStore.createOrUpdateLink(PID,
+                new DefaultLinkDescription(src, dst, INDIRECT, A2));
+
+        assertLink(DID1, P1, DID2, P2, INDIRECT, event2.subject());
+        assertAnnotationsEquals(event2.subject().annotations(), A2, A1);
+        assertEquals(LINK_UPDATED, event2.type());
+
+        // update link type
+        LinkEvent event3 = linkStore.createOrUpdateLink(PID,
+                new DefaultLinkDescription(src, dst, DIRECT, A2));
+        assertLink(DID1, P1, DID2, P2, DIRECT, event3.subject());
+        assertAnnotationsEquals(event3.subject().annotations(), A2, A1);
+        assertEquals(LINK_UPDATED, event3.type());
+
+
+        // no change
+        LinkEvent event4 = linkStore.createOrUpdateLink(PID,
+                new DefaultLinkDescription(src, dst, DIRECT));
+        assertNull("No change event expected", event4);
+
+        // update link annotation (Primary)
+        LinkEvent event5 = linkStore.createOrUpdateLink(PID,
+                new DefaultLinkDescription(src, dst, DIRECT, A2_2));
+        assertLink(DID1, P1, DID2, P2, DIRECT, event5.subject());
+        assertAnnotationsEquals(event5.subject().annotations(), A2, A2_2, A1);
+        assertEquals(LINK_UPDATED, event5.type());
+
+        // update link annotation (Ancillary)
+        LinkEvent event6 = linkStore.createOrUpdateLink(PIDA,
+                new DefaultLinkDescription(src, dst, DIRECT, A1_2));
+        assertLink(DID1, P1, DID2, P2, DIRECT, event6.subject());
+        assertAnnotationsEquals(event6.subject().annotations(), A2, A2_2, A1, A1_2);
+        assertEquals(LINK_UPDATED, event6.type());
+
+        // update link type (Ancillary) : ignored
+        LinkEvent event7 = linkStore.createOrUpdateLink(PIDA,
+                new DefaultLinkDescription(src, dst, EDGE));
+        assertNull("Ancillary change other than annotation is ignored", event7);
+    }
+
+
+    @Test
+    public final void testRemoveOrDownLink() {
+        removeOrDownLink(false);
+    }
+
+    @Test
+    public final void testRemoveOrDownLinkDurable() {
+        removeOrDownLink(true);
+    }
+
+    private void removeOrDownLink(boolean isDurable) {
+        final ConnectPoint d1P1 = new ConnectPoint(DID1, P1);
+        final ConnectPoint d2P2 = new ConnectPoint(DID2, P2);
+        LinkKey linkId1 = LinkKey.linkKey(d1P1, d2P2);
+        LinkKey linkId2 = LinkKey.linkKey(d2P2, d1P1);
+
+        putLink(linkId1, DIRECT, isDurable ? DA1 : A1);
+        putLink(linkId2, DIRECT, isDurable ? DA2 : A2);
+
+        // DID1,P1 => DID2,P2
+        // DID2,P2 => DID1,P1
+        // DID1,P2 => DID2,P3
+
+        LinkEvent event = linkStore.removeOrDownLink(d1P1, d2P2);
+        assertEquals(isDurable ? LINK_UPDATED : LINK_REMOVED, event.type());
+        assertAnnotationsEquals(event.subject().annotations(), isDurable ? DA1 : A1);
+        LinkEvent event2 = linkStore.removeOrDownLink(d1P1, d2P2);
+        assertNull(event2);
+
+        assertLink(linkId2, DIRECT, linkStore.getLink(d2P2, d1P1));
+        assertAnnotationsEquals(linkStore.getLink(d2P2, d1P1).annotations(),
+                                isDurable ? DA2 : A2);
+
+        // annotations, etc. should not survive remove
+        if (!isDurable) {
+            putLink(linkId1, DIRECT);
+            assertLink(linkId1, DIRECT, linkStore.getLink(d1P1, d2P2));
+            assertAnnotationsEquals(linkStore.getLink(d1P1, d2P2).annotations());
+        }
+    }
+
+    @Test
+    public final void testRemoveLink() {
+        final ConnectPoint d1P1 = new ConnectPoint(DID1, P1);
+        final ConnectPoint d2P2 = new ConnectPoint(DID2, P2);
+        LinkKey linkId1 = LinkKey.linkKey(d1P1, d2P2);
+        LinkKey linkId2 = LinkKey.linkKey(d2P2, d1P1);
+
+        putLink(linkId1, DIRECT, A1);
+        putLink(linkId2, DIRECT, A2);
+
+        // DID1,P1 => DID2,P2
+        // DID2,P2 => DID1,P1
+        // DID1,P2 => DID2,P3
+
+        LinkEvent event = linkStore.removeLink(d1P1, d2P2);
+        assertEquals(LINK_REMOVED, event.type());
+        assertAnnotationsEquals(event.subject().annotations(), A1);
+        LinkEvent event2 = linkStore.removeLink(d1P1, d2P2);
+        assertNull(event2);
+
+        assertLink(linkId2, DIRECT, linkStore.getLink(d2P2, d1P1));
+        assertAnnotationsEquals(linkStore.getLink(d2P2, d1P1).annotations(), A2);
+
+        // annotations, etc. should not survive remove
+        putLink(linkId1, DIRECT);
+        assertLink(linkId1, DIRECT, linkStore.getLink(d1P1, d2P2));
+        assertAnnotationsEquals(linkStore.getLink(d1P1, d2P2).annotations());
+    }
+
+    @Test
+    public final void testAncillaryVisible() {
+        ConnectPoint src = new ConnectPoint(DID1, P1);
+        ConnectPoint dst = new ConnectPoint(DID2, P2);
+
+        // add Ancillary link
+        linkStore.createOrUpdateLink(PIDA,
+                    new DefaultLinkDescription(src, dst, INDIRECT, A1));
+
+        // Ancillary only link should not be visible
+        assertEquals(1, linkStore.getLinkCount());
+        assertNotNull(linkStore.getLink(src, dst));
+    }
+
+    @Test
+    public void testDurableToNonDurable() {
+        final ConnectPoint d1P1 = new ConnectPoint(DID1, P1);
+        final ConnectPoint d2P2 = new ConnectPoint(DID2, P2);
+        LinkKey linkId1 = LinkKey.linkKey(d1P1, d2P2);
+
+        putLink(linkId1, DIRECT, DA1);
+        assertTrue("should be be durable", linkStore.getLink(d1P1, d2P2).isDurable());
+        putLink(linkId1, DIRECT, NDA1);
+        assertFalse("should not be durable", linkStore.getLink(d1P1, d2P2).isDurable());
+    }
+
+    @Test
+    public void testNonDurableToDurable() {
+        final ConnectPoint d1P1 = new ConnectPoint(DID1, P1);
+        final ConnectPoint d2P2 = new ConnectPoint(DID2, P2);
+        LinkKey linkId1 = LinkKey.linkKey(d1P1, d2P2);
+
+        putLink(linkId1, DIRECT, A1);
+        assertFalse("should not be durable", linkStore.getLink(d1P1, d2P2).isDurable());
+        putLink(linkId1, DIRECT, DA1);
+        assertTrue("should be durable", linkStore.getLink(d1P1, d2P2).isDurable());
+    }
+
+    // If Delegates should be called only on remote events,
+    // then Simple* should never call them, thus not test required.
+    @Ignore("Ignore until Delegate spec. is clear.")
+    @Test
+    public final void testEvents() throws InterruptedException {
+
+        final ConnectPoint d1P1 = new ConnectPoint(DID1, P1);
+        final ConnectPoint d2P2 = new ConnectPoint(DID2, P2);
+        final LinkKey linkId1 = LinkKey.linkKey(d1P1, d2P2);
+
+        final CountDownLatch addLatch = new CountDownLatch(1);
+        LinkStoreDelegate checkAdd = new LinkStoreDelegate() {
+            @Override
+            public void notify(LinkEvent event) {
+                assertEquals(LINK_ADDED, event.type());
+                assertLink(linkId1, INDIRECT, event.subject());
+                addLatch.countDown();
+            }
+        };
+        final CountDownLatch updateLatch = new CountDownLatch(1);
+        LinkStoreDelegate checkUpdate = new LinkStoreDelegate() {
+            @Override
+            public void notify(LinkEvent event) {
+                assertEquals(LINK_UPDATED, event.type());
+                assertLink(linkId1, DIRECT, event.subject());
+                updateLatch.countDown();
+            }
+        };
+        final CountDownLatch removeLatch = new CountDownLatch(1);
+        LinkStoreDelegate checkRemove = new LinkStoreDelegate() {
+            @Override
+            public void notify(LinkEvent event) {
+                assertEquals(LINK_REMOVED, event.type());
+                assertLink(linkId1, DIRECT, event.subject());
+                removeLatch.countDown();
+            }
+        };
+
+        linkStore.setDelegate(checkAdd);
+        putLink(linkId1, INDIRECT);
+        assertTrue("Add event fired", addLatch.await(1, TimeUnit.SECONDS));
+
+        linkStore.unsetDelegate(checkAdd);
+        linkStore.setDelegate(checkUpdate);
+        putLink(linkId1, DIRECT);
+        assertTrue("Update event fired", updateLatch.await(1, TimeUnit.SECONDS));
+
+        linkStore.unsetDelegate(checkUpdate);
+        linkStore.setDelegate(checkRemove);
+        linkStore.removeOrDownLink(d1P1, d2P2);
+        assertTrue("Remove event fired", removeLatch.await(1, TimeUnit.SECONDS));
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleMastershipStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleMastershipStore.java
new file mode 100644
index 0000000..ef92ded
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleMastershipStore.java
@@ -0,0 +1,388 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import static org.onosproject.mastership.MastershipEvent.Type.BACKUPS_CHANGED;
+import static org.onosproject.mastership.MastershipEvent.Type.MASTER_CHANGED;
+import static org.slf4j.LoggerFactory.getLogger;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.joda.time.DateTime;
+import org.onlab.packet.IpAddress;
+import org.onosproject.cluster.ClusterEventListener;
+import org.onosproject.cluster.ClusterService;
+import org.onosproject.cluster.ControllerNode;
+import org.onosproject.cluster.ControllerNode.State;
+import org.onosproject.cluster.DefaultControllerNode;
+import org.onosproject.cluster.NodeId;
+import org.onosproject.cluster.RoleInfo;
+import org.onosproject.mastership.MastershipEvent;
+import org.onosproject.mastership.MastershipStore;
+import org.onosproject.mastership.MastershipStoreDelegate;
+import org.onosproject.mastership.MastershipTerm;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.MastershipRole;
+import org.onosproject.store.AbstractStore;
+import org.slf4j.Logger;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
+
+/**
+ * Manages inventory of controller mastership over devices using
+ * trivial, non-distributed in-memory structures implementation.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleMastershipStore
+        extends AbstractStore<MastershipEvent, MastershipStoreDelegate>
+        implements MastershipStore {
+
+    private final Logger log = getLogger(getClass());
+
+    private static final int NOTHING = 0;
+    private static final int INIT = 1;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected ClusterService clusterService;
+
+    //devices mapped to their masters, to emulate multiple nodes
+    protected final Map<DeviceId, NodeId> masterMap = new HashMap<>();
+    //emulate backups with pile of nodes
+    protected final Map<DeviceId, List<NodeId>> backups = new HashMap<>();
+    //terms
+    protected final Map<DeviceId, AtomicInteger> termMap = new HashMap<>();
+
+    @Activate
+    public void activate() {
+        if (clusterService == null) {
+          // just for ease of unit test
+          final ControllerNode instance =
+                  new DefaultControllerNode(new NodeId("local"),
+                                            IpAddress.valueOf("127.0.0.1"));
+
+            clusterService = new ClusterService() {
+
+                private final DateTime creationTime = DateTime.now();
+
+                @Override
+                public ControllerNode getLocalNode() {
+                    return instance;
+                }
+
+                @Override
+                public Set<ControllerNode> getNodes() {
+                    return ImmutableSet.of(instance);
+                }
+
+                @Override
+                public ControllerNode getNode(NodeId nodeId) {
+                    if (instance.id().equals(nodeId)) {
+                        return instance;
+                    }
+                    return null;
+                }
+
+                @Override
+                public State getState(NodeId nodeId) {
+                    if (instance.id().equals(nodeId)) {
+                        return State.ACTIVE;
+                    } else {
+                        return State.INACTIVE;
+                    }
+                }
+
+                @Override
+                public DateTime getLastUpdated(NodeId nodeId) {
+                    return creationTime;
+                }
+
+                @Override
+                public void addListener(ClusterEventListener listener) {
+                }
+
+                @Override
+                public void removeListener(ClusterEventListener listener) {
+                }
+            };
+        }
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        log.info("Stopped");
+    }
+
+    @Override
+    public synchronized CompletableFuture<MastershipEvent> setMaster(NodeId nodeId, DeviceId deviceId) {
+
+        MastershipRole role = getRole(nodeId, deviceId);
+        switch (role) {
+        case MASTER:
+            // no-op
+            return CompletableFuture.completedFuture(null);
+        case STANDBY:
+        case NONE:
+            NodeId prevMaster = masterMap.put(deviceId, nodeId);
+            incrementTerm(deviceId);
+            removeFromBackups(deviceId, nodeId);
+            addToBackup(deviceId, prevMaster);
+            break;
+        default:
+            log.warn("unknown Mastership Role {}", role);
+            return null;
+        }
+
+        return CompletableFuture.completedFuture(
+                new MastershipEvent(MASTER_CHANGED, deviceId, getNodes(deviceId)));
+    }
+
+    @Override
+    public NodeId getMaster(DeviceId deviceId) {
+        return masterMap.get(deviceId);
+    }
+
+    // synchronized for atomic read
+    @Override
+    public synchronized RoleInfo getNodes(DeviceId deviceId) {
+        return new RoleInfo(masterMap.get(deviceId),
+                            backups.getOrDefault(deviceId, ImmutableList.of()));
+    }
+
+    @Override
+    public Set<DeviceId> getDevices(NodeId nodeId) {
+        Set<DeviceId> ids = new HashSet<>();
+        for (Map.Entry<DeviceId, NodeId> d : masterMap.entrySet()) {
+            if (Objects.equals(d.getValue(), nodeId)) {
+                ids.add(d.getKey());
+            }
+        }
+        return ids;
+    }
+
+    @Override
+    public synchronized CompletableFuture<MastershipRole> requestRole(DeviceId deviceId) {
+        //query+possible reelection
+        NodeId node = clusterService.getLocalNode().id();
+        MastershipRole role = getRole(node, deviceId);
+
+        switch (role) {
+            case MASTER:
+                return CompletableFuture.completedFuture(MastershipRole.MASTER);
+            case STANDBY:
+                if (getMaster(deviceId) == null) {
+                    // no master => become master
+                    masterMap.put(deviceId, node);
+                    incrementTerm(deviceId);
+                    // remove from backup list
+                    removeFromBackups(deviceId, node);
+                    notifyDelegate(new MastershipEvent(MASTER_CHANGED, deviceId,
+                                                       getNodes(deviceId)));
+                    return CompletableFuture.completedFuture(MastershipRole.MASTER);
+                }
+                return CompletableFuture.completedFuture(MastershipRole.STANDBY);
+            case NONE:
+                if (getMaster(deviceId) == null) {
+                    // no master => become master
+                    masterMap.put(deviceId, node);
+                    incrementTerm(deviceId);
+                    notifyDelegate(new MastershipEvent(MASTER_CHANGED, deviceId,
+                                                       getNodes(deviceId)));
+                    return CompletableFuture.completedFuture(MastershipRole.MASTER);
+                }
+                // add to backup list
+                if (addToBackup(deviceId, node)) {
+                    notifyDelegate(new MastershipEvent(BACKUPS_CHANGED, deviceId,
+                                                       getNodes(deviceId)));
+                }
+                return CompletableFuture.completedFuture(MastershipRole.STANDBY);
+            default:
+                log.warn("unknown Mastership Role {}", role);
+        }
+        return CompletableFuture.completedFuture(role);
+    }
+
+    // add to backup if not there already, silently ignores null node
+    private synchronized boolean addToBackup(DeviceId deviceId, NodeId nodeId) {
+        boolean modified = false;
+        List<NodeId> stbys = backups.getOrDefault(deviceId, new ArrayList<>());
+        if (nodeId != null && !stbys.contains(nodeId)) {
+            stbys.add(nodeId);
+            modified = true;
+        }
+        backups.put(deviceId, stbys);
+        return modified;
+    }
+
+    private synchronized boolean removeFromBackups(DeviceId deviceId, NodeId node) {
+        List<NodeId> stbys = backups.getOrDefault(deviceId, new ArrayList<>());
+        boolean modified = stbys.remove(node);
+        backups.put(deviceId, stbys);
+        return modified;
+    }
+
+    private synchronized void incrementTerm(DeviceId deviceId) {
+        AtomicInteger term = termMap.getOrDefault(deviceId, new AtomicInteger(NOTHING));
+        term.incrementAndGet();
+        termMap.put(deviceId, term);
+    }
+
+    @Override
+    public MastershipRole getRole(NodeId nodeId, DeviceId deviceId) {
+        //just query
+        NodeId current = masterMap.get(deviceId);
+        MastershipRole role;
+
+        if (current != null && current.equals(nodeId)) {
+            return MastershipRole.MASTER;
+        }
+
+        if (backups.getOrDefault(deviceId, Collections.emptyList()).contains(nodeId)) {
+            role = MastershipRole.STANDBY;
+        } else {
+            role = MastershipRole.NONE;
+        }
+        return role;
+    }
+
+    // synchronized for atomic read
+    @Override
+    public synchronized MastershipTerm getTermFor(DeviceId deviceId) {
+        if ((termMap.get(deviceId) == null)) {
+            return MastershipTerm.of(masterMap.get(deviceId), NOTHING);
+        }
+        return MastershipTerm.of(
+                masterMap.get(deviceId), termMap.get(deviceId).get());
+    }
+
+    @Override
+    public synchronized CompletableFuture<MastershipEvent> setStandby(NodeId nodeId, DeviceId deviceId) {
+        MastershipRole role = getRole(nodeId, deviceId);
+        switch (role) {
+        case MASTER:
+            NodeId backup = reelect(deviceId, nodeId);
+            if (backup == null) {
+                // no master alternative
+                masterMap.remove(deviceId);
+                // TODO: Should there be new event type for no MASTER?
+                return CompletableFuture.completedFuture(
+                        new MastershipEvent(MASTER_CHANGED, deviceId, getNodes(deviceId)));
+            } else {
+                NodeId prevMaster = masterMap.put(deviceId, backup);
+                incrementTerm(deviceId);
+                addToBackup(deviceId, prevMaster);
+                return CompletableFuture.completedFuture(
+                        new MastershipEvent(MASTER_CHANGED, deviceId, getNodes(deviceId)));
+            }
+
+        case STANDBY:
+        case NONE:
+            boolean modified = addToBackup(deviceId, nodeId);
+            if (modified) {
+                return CompletableFuture.completedFuture(
+                        new MastershipEvent(BACKUPS_CHANGED, deviceId, getNodes(deviceId)));
+            }
+            break;
+
+        default:
+            log.warn("unknown Mastership Role {}", role);
+        }
+        return null;
+    }
+
+    //dumbly selects next-available node that's not the current one
+    //emulate leader election
+    private synchronized NodeId reelect(DeviceId did, NodeId nodeId) {
+        List<NodeId> stbys = backups.getOrDefault(did, Collections.emptyList());
+        NodeId backup = null;
+        for (NodeId n : stbys) {
+            if (!n.equals(nodeId)) {
+                backup = n;
+                break;
+            }
+        }
+        stbys.remove(backup);
+        return backup;
+    }
+
+    @Override
+    public synchronized CompletableFuture<MastershipEvent> relinquishRole(NodeId nodeId, DeviceId deviceId) {
+        MastershipRole role = getRole(nodeId, deviceId);
+        switch (role) {
+        case MASTER:
+            NodeId backup = reelect(deviceId, nodeId);
+            masterMap.put(deviceId, backup);
+            incrementTerm(deviceId);
+            return CompletableFuture.completedFuture(
+                    new MastershipEvent(MASTER_CHANGED, deviceId, getNodes(deviceId)));
+
+        case STANDBY:
+            if (removeFromBackups(deviceId, nodeId)) {
+                return CompletableFuture.completedFuture(
+                    new MastershipEvent(BACKUPS_CHANGED, deviceId, getNodes(deviceId)));
+            }
+            break;
+
+        case NONE:
+            break;
+
+        default:
+            log.warn("unknown Mastership Role {}", role);
+        }
+        return CompletableFuture.completedFuture(null);
+    }
+
+    @Override
+    public synchronized void relinquishAllRole(NodeId nodeId) {
+        List<CompletableFuture<MastershipEvent>> eventFutures = new ArrayList<>();
+        Set<DeviceId> toRelinquish = new HashSet<>();
+
+        masterMap.entrySet().stream()
+            .filter(entry -> nodeId.equals(entry.getValue()))
+            .forEach(entry -> toRelinquish.add(entry.getKey()));
+
+        backups.entrySet().stream()
+            .filter(entry -> entry.getValue().contains(nodeId))
+            .forEach(entry -> toRelinquish.add(entry.getKey()));
+
+        toRelinquish.forEach(deviceId -> {
+            eventFutures.add(relinquishRole(nodeId, deviceId));
+        });
+
+        eventFutures.forEach(future -> {
+            future.whenComplete((event, error) -> {
+                notifyDelegate(event);
+            });
+        });
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleMastershipStoreTest.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleMastershipStoreTest.java
new file mode 100644
index 0000000..672fc50
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleMastershipStoreTest.java
@@ -0,0 +1,184 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.onosproject.cluster.NodeId;
+import org.onosproject.mastership.MastershipEvent;
+import org.onosproject.mastership.MastershipTerm;
+import org.onosproject.net.DeviceId;
+
+import com.google.common.collect.Sets;
+import com.google.common.util.concurrent.Futures;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.onosproject.mastership.MastershipEvent.Type.*;
+import static org.onosproject.net.MastershipRole.*;
+
+/**
+ * Test for the simple MastershipStore implementation.
+ */
+public class SimpleMastershipStoreTest {
+
+    private static final DeviceId DID1 = DeviceId.deviceId("of:01");
+    private static final DeviceId DID2 = DeviceId.deviceId("of:02");
+    private static final DeviceId DID3 = DeviceId.deviceId("of:03");
+    private static final DeviceId DID4 = DeviceId.deviceId("of:04");
+
+    private static final NodeId N1 = new NodeId("local");
+    private static final NodeId N2 = new NodeId("other");
+
+    private SimpleMastershipStore sms;
+
+    @Before
+    public void setUp() throws Exception {
+        sms = new SimpleMastershipStore();
+        sms.activate();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        sms.deactivate();
+    }
+
+    @Test
+    public void getRole() {
+        //special case, no backup or master
+        put(DID1, N1, false, false);
+        assertEquals("wrong role", NONE, sms.getRole(N1, DID1));
+
+        //backup exists but we aren't mapped
+        put(DID2, N1, false, true);
+        assertEquals("wrong role", STANDBY, sms.getRole(N1, DID2));
+
+        //N2 is master
+        put(DID3, N2, true, true);
+        assertEquals("wrong role", MASTER, sms.getRole(N2, DID3));
+
+        //N2 is master but N1 is only in backups set
+        put(DID4, N1, false, true);
+        put(DID4, N2, true, false);
+        assertEquals("wrong role", STANDBY, sms.getRole(N1, DID4));
+    }
+
+    @Test
+    public void getMaster() {
+        put(DID3, N2, true, true);
+        assertEquals("wrong role", MASTER, sms.getRole(N2, DID3));
+        assertEquals("wrong device", N2, sms.getMaster(DID3));
+    }
+
+    @Test
+    public void setMaster() {
+        put(DID1, N1, false, false);
+        assertEquals("wrong event", MASTER_CHANGED, Futures.getUnchecked(sms.setMaster(N1, DID1)).type());
+        assertEquals("wrong role", MASTER, sms.getRole(N1, DID1));
+        //set node that's already master - should be ignored
+        assertNull("wrong event", Futures.getUnchecked(sms.setMaster(N1, DID1)));
+
+        //set STANDBY to MASTER
+        put(DID2, N1, false, true);
+        assertEquals("wrong role", STANDBY, sms.getRole(N1, DID2));
+        assertEquals("wrong event", MASTER_CHANGED, Futures.getUnchecked(sms.setMaster(N1, DID2)).type());
+        assertEquals("wrong role", MASTER, sms.getRole(N1, DID2));
+    }
+
+    @Test
+    public void getDevices() {
+        Set<DeviceId> d = Sets.newHashSet(DID1, DID2);
+
+        put(DID1, N2, true, true);
+        put(DID2, N2, true, true);
+        put(DID3, N1, true, true);
+        assertTrue("wrong devices", d.equals(sms.getDevices(N2)));
+    }
+
+    @Test
+    public void getTermFor() {
+        put(DID1, N1, true, true);
+        assertEquals("wrong term", MastershipTerm.of(N1, 0), sms.getTermFor(DID1));
+
+        //switch to N2 and back - 2 term switches
+        sms.setMaster(N2, DID1);
+        sms.setMaster(N1, DID1);
+        assertEquals("wrong term", MastershipTerm.of(N1, 2), sms.getTermFor(DID1));
+    }
+
+    @Test
+    public void requestRole() {
+        //NONE - become MASTER
+        put(DID1, N1, false, false);
+        assertEquals("wrong role", MASTER, Futures.getUnchecked(sms.requestRole(DID1)));
+
+        //was STANDBY - become MASTER
+        put(DID2, N1, false, true);
+        assertEquals("wrong role", MASTER, Futures.getUnchecked(sms.requestRole(DID2)));
+
+        //other MASTER - stay STANDBY
+        put(DID3, N2, true, false);
+        assertEquals("wrong role", STANDBY, Futures.getUnchecked(sms.requestRole(DID3)));
+
+        //local (N1) is MASTER - stay MASTER
+        put(DID4, N1, true, true);
+        assertEquals("wrong role", MASTER, Futures.getUnchecked(sms.requestRole(DID4)));
+    }
+
+    @Test
+    public void unsetMaster() {
+        //NONE - record backup but take no other action
+        put(DID1, N1, false, false);
+        sms.setStandby(N1, DID1);
+        assertTrue("not backed up", sms.backups.get(DID1).contains(N1));
+        int prev = sms.termMap.get(DID1).get();
+        sms.setStandby(N1, DID1);
+        assertEquals("term should not change", prev, sms.termMap.get(DID1).get());
+
+        //no backup, MASTER
+        put(DID1, N1, true, false);
+        assertNull("expect no MASTER event", Futures.getUnchecked(sms.setStandby(N1, DID1)).roleInfo().master());
+        assertNull("wrong node", sms.masterMap.get(DID1));
+
+        //backup, switch
+        sms.masterMap.clear();
+        put(DID1, N1, true, true);
+        put(DID1, N2, false, true);
+        put(DID2, N2, true, true);
+        MastershipEvent event = Futures.getUnchecked(sms.setStandby(N1, DID1));
+        assertEquals("wrong event", MASTER_CHANGED, event.type());
+        assertEquals("wrong master", N2, event.roleInfo().master());
+    }
+
+    //helper to populate master/backup structures
+    private void put(DeviceId dev, NodeId node, boolean master, boolean backup) {
+        if (master) {
+            sms.masterMap.put(dev, node);
+        } else if (backup) {
+            List<NodeId> stbys = sms.backups.getOrDefault(dev, new ArrayList<>());
+            stbys.add(node);
+            sms.backups.put(dev, stbys);
+        }
+        sms.termMap.put(dev, new AtomicInteger());
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimplePacketStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimplePacketStore.java
new file mode 100644
index 0000000..81cef49
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimplePacketStore.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.collect.Sets;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.net.packet.OutboundPacket;
+import org.onosproject.net.packet.PacketEvent;
+import org.onosproject.net.packet.PacketEvent.Type;
+import org.onosproject.net.packet.PacketRequest;
+import org.onosproject.net.packet.PacketStore;
+import org.onosproject.net.packet.PacketStoreDelegate;
+import org.onosproject.store.AbstractStore;
+
+
+import java.util.Collections;
+import java.util.Set;
+
+/**
+ * Simple single instance implementation of the packet store.
+ */
+@Component(immediate = true)
+@Service
+public class SimplePacketStore
+        extends AbstractStore<PacketEvent, PacketStoreDelegate>
+        implements PacketStore {
+
+    private Set<PacketRequest> requests = Sets.newConcurrentHashSet();
+
+    @Override
+    public void emit(OutboundPacket packet) {
+        notifyDelegate(new PacketEvent(Type.EMIT, packet));
+    }
+
+    @Override
+    public boolean requestPackets(PacketRequest request) {
+        return requests.add(request);
+    }
+
+    @Override
+    public Set<PacketRequest> existingRequests() {
+        return Collections.unmodifiableSet(requests);
+    }
+
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleStatisticStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleStatisticStore.java
new file mode 100644
index 0000000..370686f
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleStatisticStore.java
@@ -0,0 +1,211 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.collect.Sets;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.flow.FlowEntry;
+import org.onosproject.net.flow.FlowRule;
+import org.onosproject.net.flow.instructions.Instruction;
+import org.onosproject.net.flow.instructions.Instructions;
+import org.onosproject.net.statistic.StatisticStore;
+import org.slf4j.Logger;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.slf4j.LoggerFactory.getLogger;
+
+
+/**
+ * Maintains statistics using RPC calls to collect stats from remote instances
+ * on demand.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleStatisticStore implements StatisticStore {
+
+    private final Logger log = getLogger(getClass());
+
+    private Map<ConnectPoint, InternalStatisticRepresentation>
+            representations = new ConcurrentHashMap<>();
+
+    private Map<ConnectPoint, Set<FlowEntry>> previous = new ConcurrentHashMap<>();
+    private Map<ConnectPoint, Set<FlowEntry>> current = new ConcurrentHashMap<>();
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        log.info("Stopped");
+    }
+
+    @Override
+    public void prepareForStatistics(FlowRule rule) {
+        ConnectPoint cp = buildConnectPoint(rule);
+        if (cp == null) {
+            return;
+        }
+        InternalStatisticRepresentation rep;
+        synchronized (representations) {
+            rep = getOrCreateRepresentation(cp);
+        }
+        rep.prepare();
+    }
+
+    @Override
+    public synchronized void removeFromStatistics(FlowRule rule) {
+        ConnectPoint cp = buildConnectPoint(rule);
+        if (cp == null) {
+            return;
+        }
+        InternalStatisticRepresentation rep = representations.get(cp);
+        if (rep != null && rep.remove(rule)) {
+            updatePublishedStats(cp, Collections.emptySet());
+        }
+        Set<FlowEntry> values = current.get(cp);
+        if (values != null) {
+            values.remove(rule);
+        }
+        values = previous.get(cp);
+        if (values != null) {
+            values.remove(rule);
+        }
+
+    }
+
+    @Override
+    public void addOrUpdateStatistic(FlowEntry rule) {
+        ConnectPoint cp = buildConnectPoint(rule);
+        if (cp == null) {
+            return;
+        }
+        InternalStatisticRepresentation rep = representations.get(cp);
+        if (rep != null && rep.submit(rule)) {
+            updatePublishedStats(cp, rep.get());
+        }
+    }
+
+    private synchronized void updatePublishedStats(ConnectPoint cp,
+                                                   Set<FlowEntry> flowEntries) {
+        Set<FlowEntry> curr = current.get(cp);
+        if (curr == null) {
+            curr = new HashSet<>();
+        }
+        previous.put(cp, curr);
+        current.put(cp, flowEntries);
+
+    }
+
+    @Override
+    public Set<FlowEntry> getCurrentStatistic(ConnectPoint connectPoint) {
+        return getCurrentStatisticInternal(connectPoint);
+    }
+
+    private synchronized Set<FlowEntry> getCurrentStatisticInternal(ConnectPoint connectPoint) {
+        return current.get(connectPoint);
+    }
+
+    @Override
+    public Set<FlowEntry> getPreviousStatistic(ConnectPoint connectPoint) {
+        return getPreviousStatisticInternal(connectPoint);
+    }
+
+    private synchronized Set<FlowEntry> getPreviousStatisticInternal(ConnectPoint connectPoint) {
+        return previous.get(connectPoint);
+    }
+
+    private InternalStatisticRepresentation getOrCreateRepresentation(ConnectPoint cp) {
+
+        if (representations.containsKey(cp)) {
+            return representations.get(cp);
+        } else {
+            InternalStatisticRepresentation rep = new InternalStatisticRepresentation();
+            representations.put(cp, rep);
+            return rep;
+        }
+
+    }
+
+    private ConnectPoint buildConnectPoint(FlowRule rule) {
+        PortNumber port = getOutput(rule);
+
+        if (port == null) {
+            return null;
+        }
+        ConnectPoint cp = new ConnectPoint(rule.deviceId(), port);
+        return cp;
+    }
+
+    private PortNumber getOutput(FlowRule rule) {
+        for (Instruction i : rule.treatment().immediate()) {
+            if (i.type() == Instruction.Type.OUTPUT) {
+                Instructions.OutputInstruction out = (Instructions.OutputInstruction) i;
+                return out.port();
+            }
+            if (i.type() == Instruction.Type.DROP) {
+                return PortNumber.P0;
+            }
+        }
+        return null;
+    }
+
+    private class InternalStatisticRepresentation {
+
+        private final AtomicInteger counter = new AtomicInteger(0);
+        private final Set<FlowEntry> rules = new HashSet<>();
+
+        public void prepare() {
+            counter.incrementAndGet();
+        }
+
+        public synchronized boolean remove(FlowRule rule) {
+            rules.remove(rule);
+            return counter.decrementAndGet() == 0;
+        }
+
+        public synchronized boolean submit(FlowEntry rule) {
+            if (rules.contains(rule)) {
+                rules.remove(rule);
+            }
+            rules.add(rule);
+            if (counter.get() == 0) {
+                return true;
+            } else {
+                return counter.decrementAndGet() == 0;
+            }
+        }
+
+        public synchronized Set<FlowEntry> get() {
+            counter.set(rules.size());
+            return Sets.newHashSet(rules);
+        }
+
+    }
+
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleTopologyStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleTopologyStore.java
new file mode 100644
index 0000000..cd564f0
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleTopologyStore.java
@@ -0,0 +1,156 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.event.Event;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Link;
+import org.onosproject.net.Path;
+import org.onosproject.net.provider.ProviderId;
+import org.onosproject.net.topology.ClusterId;
+import org.onosproject.net.topology.GraphDescription;
+import org.onosproject.net.topology.LinkWeight;
+import org.onosproject.net.topology.Topology;
+import org.onosproject.net.topology.TopologyCluster;
+import org.onosproject.net.topology.TopologyEvent;
+import org.onosproject.net.topology.TopologyGraph;
+import org.onosproject.net.topology.TopologyStore;
+import org.onosproject.net.topology.TopologyStoreDelegate;
+import org.onosproject.store.AbstractStore;
+import org.slf4j.Logger;
+
+import java.util.List;
+import java.util.Set;
+
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Manages inventory of topology snapshots using trivial in-memory
+ * structures implementation.
+ */
+@Component(immediate = true)
+@Service
+public class SimpleTopologyStore
+        extends AbstractStore<TopologyEvent, TopologyStoreDelegate>
+        implements TopologyStore {
+
+    private final Logger log = getLogger(getClass());
+
+    private volatile DefaultTopology current;
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        log.info("Stopped");
+    }
+    @Override
+    public Topology currentTopology() {
+        return current;
+    }
+
+    @Override
+    public boolean isLatest(Topology topology) {
+        // Topology is current only if it is the same as our current topology
+        return topology == current;
+    }
+
+    @Override
+    public TopologyGraph getGraph(Topology topology) {
+        return defaultTopology(topology).getGraph();
+    }
+
+    @Override
+    public Set<TopologyCluster> getClusters(Topology topology) {
+        return defaultTopology(topology).getClusters();
+    }
+
+    @Override
+    public TopologyCluster getCluster(Topology topology, ClusterId clusterId) {
+        return defaultTopology(topology).getCluster(clusterId);
+    }
+
+    @Override
+    public Set<DeviceId> getClusterDevices(Topology topology, TopologyCluster cluster) {
+        return defaultTopology(topology).getClusterDevices(cluster);
+    }
+
+    @Override
+    public Set<Link> getClusterLinks(Topology topology, TopologyCluster cluster) {
+        return defaultTopology(topology).getClusterLinks(cluster);
+    }
+
+    @Override
+    public Set<Path> getPaths(Topology topology, DeviceId src, DeviceId dst) {
+        return defaultTopology(topology).getPaths(src, dst);
+    }
+
+    @Override
+    public Set<Path> getPaths(Topology topology, DeviceId src, DeviceId dst,
+                              LinkWeight weight) {
+        return defaultTopology(topology).getPaths(src, dst, weight);
+    }
+
+    @Override
+    public boolean isInfrastructure(Topology topology, ConnectPoint connectPoint) {
+        return defaultTopology(topology).isInfrastructure(connectPoint);
+    }
+
+    @Override
+    public boolean isBroadcastPoint(Topology topology, ConnectPoint connectPoint) {
+        return defaultTopology(topology).isBroadcastPoint(connectPoint);
+    }
+
+    @Override
+    public TopologyEvent updateTopology(ProviderId providerId,
+                                        GraphDescription graphDescription,
+                                        List<Event> reasons) {
+        // First off, make sure that what we're given is indeed newer than
+        // what we already have.
+        if (current != null && graphDescription.timestamp() < current.time()) {
+            return null;
+        }
+
+        // Have the default topology construct self from the description data.
+        DefaultTopology newTopology =
+                new DefaultTopology(providerId, graphDescription);
+
+        // Promote the new topology to current and return a ready-to-send event.
+        synchronized (this) {
+            current = newTopology;
+            return new TopologyEvent(TopologyEvent.Type.TOPOLOGY_CHANGED,
+                                     current, reasons);
+        }
+    }
+
+    // Validates the specified topology and returns it as a default
+    private DefaultTopology defaultTopology(Topology topology) {
+        if (topology instanceof DefaultTopology) {
+            return (DefaultTopology) topology;
+        }
+        throw new IllegalArgumentException("Topology class " + topology.getClass() +
+                                                   " not supported");
+    }
+
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SystemClockTimestamp.java b/core/common/src/test/java/org/onosproject/store/trivial/SystemClockTimestamp.java
new file mode 100644
index 0000000..2ee4194
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SystemClockTimestamp.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.trivial;
+
+import com.google.common.base.MoreObjects;
+import com.google.common.collect.ComparisonChain;
+import org.onosproject.store.Timestamp;
+
+import java.util.Objects;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+/**
+ * A Timestamp that derives its value from the system clock time (in ns)
+ * on the controller where it is generated.
+ */
+public class SystemClockTimestamp implements Timestamp {
+
+    private final long nanoTimestamp;
+
+    public SystemClockTimestamp() {
+        nanoTimestamp = System.nanoTime();
+    }
+
+    public SystemClockTimestamp(long timestamp) {
+        nanoTimestamp = timestamp;
+    }
+
+    @Override
+    public int compareTo(Timestamp o) {
+        checkArgument(o instanceof SystemClockTimestamp,
+                "Must be SystemClockTimestamp", o);
+        SystemClockTimestamp that = (SystemClockTimestamp) o;
+
+        return ComparisonChain.start()
+                .compare(this.nanoTimestamp, that.nanoTimestamp)
+                .result();
+    }
+    @Override
+    public int hashCode() {
+        return Objects.hash(nanoTimestamp);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (!(obj instanceof SystemClockTimestamp)) {
+            return false;
+        }
+        SystemClockTimestamp that = (SystemClockTimestamp) obj;
+        return Objects.equals(this.nanoTimestamp, that.nanoTimestamp);
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass())
+                    .add("nanoTimestamp", nanoTimestamp)
+                    .toString();
+    }
+
+    public long nanoTimestamp() {
+        return nanoTimestamp;
+    }
+
+    public long systemTimestamp() {
+        return nanoTimestamp / 1_000_000; // convert ns to ms
+    }
+}
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/package-info.java b/core/common/src/test/java/org/onosproject/store/trivial/package-info.java
new file mode 100644
index 0000000..2b0c36b
--- /dev/null
+++ b/core/common/src/test/java/org/onosproject/store/trivial/package-info.java
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Implementations of in-memory stores suitable for unit testing and
+ * experimentation; not for production use.
+ */
+package org.onosproject.store.trivial;