diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManager.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceManager.java
similarity index 99%
rename from core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManager.java
rename to core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceManager.java
index 135edd9..221a249 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManager.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceManager.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.net.trivial.impl;
+package org.onlab.onos.net.trivial.device.impl;
 
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceStore.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceStore.java
similarity index 99%
rename from core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceStore.java
rename to core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceStore.java
index 1c1502e..6317b14 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceStore.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceStore.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.net.trivial.impl;
+package org.onlab.onos.net.trivial.device.impl;
 
 import com.google.common.collect.ImmutableList;
 import org.onlab.onos.net.DefaultDevice;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/DefaultTopologyDescription.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/DefaultTopologyDescription.java
deleted file mode 100644
index c438146..0000000
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/DefaultTopologyDescription.java
+++ /dev/null
@@ -1,250 +0,0 @@
-package org.onlab.onos.net.trivial.impl;
-
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Maps;
-import com.google.common.collect.Sets;
-import org.onlab.graph.AdjacencyListsGraph;
-import org.onlab.graph.DijkstraGraphSearch;
-import org.onlab.graph.Graph;
-import org.onlab.graph.GraphPathSearch;
-import org.onlab.onos.net.ConnectPoint;
-import org.onlab.onos.net.Device;
-import org.onlab.onos.net.DeviceId;
-import org.onlab.onos.net.Link;
-import org.onlab.onos.net.topology.ClusterId;
-import org.onlab.onos.net.topology.LinkWeight;
-import org.onlab.onos.net.topology.TopoEdge;
-import org.onlab.onos.net.topology.TopoVertex;
-import org.onlab.onos.net.topology.TopologyCluster;
-import org.onlab.onos.net.topology.TopologyDescription;
-
-import java.util.Map;
-import java.util.Objects;
-import java.util.Set;
-
-import static com.google.common.base.MoreObjects.toStringHelper;
-import static org.onlab.graph.GraphPathSearch.Result;
-import static org.onlab.onos.net.Link.Type.INDIRECT;
-
-/**
- * Default implementation of an immutable topology data carrier.
- */
-class DefaultTopologyDescription implements TopologyDescription {
-
-    private static final GraphPathSearch<TopoVertex, TopoEdge> DIJKSTRA =
-            new DijkstraGraphSearch<>();
-
-    private final long nanos;
-    private final Map<DeviceId, TopoVertex> vertexesById = Maps.newHashMap();
-    private final Graph<TopoVertex, TopoEdge> graph;
-    private final Map<DeviceId, Result<TopoVertex, TopoEdge>> results;
-    private final Map<ClusterId, TopologyCluster> clusters;
-//    private final Multimap<ClusterId, DeviceId> clusterDevices;
-//    private final Multimap<ClusterId, Link> clusterLinks;
-//    private final Map<DeviceId, TopologyCluster> deviceClusters;
-
-
-    DefaultTopologyDescription(long nanos, Iterable<Device> devices, Iterable<Link> links) {
-        this.nanos = nanos;
-        this.graph = buildGraph(devices, links);
-        this.results = computeDefaultPaths();
-        this.clusters = computeClusters();
-//        this.clusterDevices = clusterDevices;
-//        this.clusterLinks = clusterLinks;
-//        this.deviceClusters = deviceClusters;
-    }
-
-    // Constructs the topology graph using the supplied devices and links.
-    private Graph<TopoVertex, TopoEdge> buildGraph(Iterable<Device> devices,
-                                                   Iterable<Link> links) {
-        Graph<TopoVertex, TopoEdge> graph =
-                new AdjacencyListsGraph<>(buildVertexes(devices),
-                                          buildEdges(links));
-        return graph;
-    }
-
-    // Builds a set of topology vertexes from the specified list of devices
-    private Set<TopoVertex> buildVertexes(Iterable<Device> devices) {
-        Set<TopoVertex> vertexes = Sets.newHashSet();
-        for (Device device : devices) {
-            TopoVertex vertex = new TVertex(device.id());
-            vertexesById.put(vertex.deviceId(), vertex);
-            vertexes.add(vertex);
-        }
-        return vertexes;
-    }
-
-    // Builds a set of topology vertexes from the specified list of links
-    private Set<TopoEdge> buildEdges(Iterable<Link> links) {
-        Set<TopoEdge> edges = Sets.newHashSet();
-        for (Link link : links) {
-            edges.add(new TEdge(vertexOf(link.src()), vertexOf(link.dst()), link));
-        }
-        return edges;
-    }
-
-    // Computes the default shortest paths for all source/dest pairs using
-    // the multi-path Dijkstra and hop-count as path cost.
-    private Map<DeviceId, Result<TopoVertex, TopoEdge>> computeDefaultPaths() {
-        LinkWeight weight = new HopCountLinkWeight(graph.getVertexes().size());
-        Map<DeviceId, Result<TopoVertex, TopoEdge>> results = Maps.newHashMap();
-
-        // Search graph paths for each source to all destinations.
-        for (TopoVertex src : vertexesById.values()) {
-            results.put(src.deviceId(), DIJKSTRA.search(graph, src, null, weight));
-        }
-        return results;
-    }
-
-    // Computes topology SCC clusters using Tarjan algorithm.
-    private Map<ClusterId, TopologyCluster> computeClusters() {
-        Map<ClusterId, TopologyCluster> clusters = Maps.newHashMap();
-        return clusters;
-    }
-
-    // Fetches a vertex corresponding to the given connection point device.
-    private TopoVertex vertexOf(ConnectPoint connectPoint) {
-        DeviceId id = connectPoint.deviceId();
-        TopoVertex vertex = vertexesById.get(id);
-        if (vertex == null) {
-            // If vertex does not exist, create one and register it.
-            vertex = new TVertex(id);
-            vertexesById.put(id, vertex);
-        }
-        return vertex;
-    }
-
-    @Override
-    public long timestamp() {
-        return nanos;
-    }
-
-    @Override
-    public Graph<TopoVertex, TopoEdge> graph() {
-        return graph;
-    }
-
-    @Override
-    public Result<TopoVertex, TopoEdge> pathResults(DeviceId srcDeviceId) {
-        return results.get(srcDeviceId);
-    }
-
-    @Override
-    public Set<TopologyCluster> clusters() {
-        return ImmutableSet.copyOf(clusters.values());
-    }
-
-    @Override
-    public Set<DeviceId> clusterDevices(TopologyCluster cluster) {
-        return null; // clusterDevices.get(cluster.id());
-    }
-
-    @Override
-    public Set<Link> clusterLinks(TopologyCluster cluster) {
-        return null; // clusterLinks.get(cluster.id());
-    }
-
-    @Override
-    public TopologyCluster clusterFor(DeviceId deviceId) {
-        return null; // deviceClusters.get(deviceId);
-    }
-
-    // Implementation of the topology vertex backed by a device id
-    private static class TVertex implements TopoVertex {
-
-        private final DeviceId deviceId;
-
-        public TVertex(DeviceId deviceId) {
-            this.deviceId = deviceId;
-        }
-
-        @Override
-        public DeviceId deviceId() {
-            return deviceId;
-        }
-
-        @Override
-        public int hashCode() {
-            return Objects.hash(deviceId);
-        }
-
-        @Override
-        public boolean equals(Object obj) {
-            if (obj instanceof TVertex) {
-                final TVertex other = (TVertex) obj;
-                return Objects.equals(this.deviceId, other.deviceId);
-            }
-            return false;
-        }
-
-        @Override
-        public String toString() {
-            return deviceId.toString();
-        }
-    }
-
-    // Implementation of the topology edge backed by a link
-    private class TEdge implements TopoEdge {
-        private final Link link;
-        private final TopoVertex src;
-        private final TopoVertex dst;
-
-        public TEdge(TopoVertex src, TopoVertex dst, Link link) {
-            this.src = src;
-            this.dst = dst;
-            this.link = link;
-        }
-
-        @Override
-        public Link link() {
-            return link;
-        }
-
-        @Override
-        public TopoVertex src() {
-            return src;
-        }
-
-        @Override
-        public TopoVertex dst() {
-            return dst;
-        }
-
-        @Override
-        public int hashCode() {
-            return Objects.hash(link);
-        }
-
-        @Override
-        public boolean equals(Object obj) {
-            if (obj instanceof TEdge) {
-                final TEdge other = (TEdge) obj;
-                return Objects.equals(this.link, other.link);
-            }
-            return false;
-        }
-
-        @Override
-        public String toString() {
-            return toStringHelper(this).add("src", src).add("dst", dst).toString();
-        }
-    }
-
-    // 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 class HopCountLinkWeight implements LinkWeight {
-        private final int indirectLinkCost;
-
-        public HopCountLinkWeight(int indirectLinkCost) {
-            this.indirectLinkCost = indirectLinkCost;
-        }
-
-        @Override
-        public double weight(TopoEdge edge) {
-            // To force preference to use direct paths first, make indirect
-            // links as expensive as the linear vertex traversal.
-            return edge.link().type() == INDIRECT ? indirectLinkCost : 1;
-        }
-    }
-
-}
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkManager.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkManager.java
similarity index 99%
rename from core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkManager.java
rename to core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkManager.java
index 1930ea1..a817bb6 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkManager.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkManager.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.net.trivial.impl;
+package org.onlab.onos.net.trivial.link.impl;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 import static org.slf4j.LoggerFactory.getLogger;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkStore.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkStore.java
similarity index 99%
rename from core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkStore.java
rename to core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkStore.java
index 9de3d5b..2ba7a30 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkStore.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkStore.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.net.trivial.impl;
+package org.onlab.onos.net.trivial.link.impl;
 
 import com.google.common.collect.HashMultimap;
 import com.google.common.collect.ImmutableSet;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/DefaultTopology.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopology.java
similarity index 96%
rename from core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/DefaultTopology.java
rename to core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopology.java
index cb55819..c20acd8 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/DefaultTopology.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopology.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.net.trivial.impl;
+package org.onlab.onos.net.trivial.topology.impl;
 
 import org.onlab.onos.net.AbstractModel;
 import org.onlab.onos.net.provider.ProviderId;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyManager.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyManager.java
similarity index 98%
rename from core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyManager.java
rename to core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyManager.java
index 33b2a18..70f001c 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyManager.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyManager.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.net.trivial.impl;
+package org.onlab.onos.net.trivial.topology.impl;
 
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyStore.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyStore.java
similarity index 98%
rename from core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyStore.java
rename to core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyStore.java
index 7944a53..1b9766d 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyStore.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyStore.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.net.trivial.impl;
+package org.onlab.onos.net.trivial.topology.impl;
 
 import org.onlab.graph.Graph;
 import org.onlab.onos.event.Event;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/DefaultTopoEdge.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/DefaultTopoEdge.java
new file mode 100644
index 0000000..d940754
--- /dev/null
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/DefaultTopoEdge.java
@@ -0,0 +1,68 @@
+package org.onlab.onos.net.trivial.topology.provider.impl;
+
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.topology.TopoEdge;
+import org.onlab.onos.net.topology.TopoVertex;
+
+import java.util.Objects;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+
+/**
+ * Implementation of the topology edge backed by a link.
+ */
+class DefaultTopoEdge implements TopoEdge {
+
+    private final Link link;
+    private final TopoVertex src;
+    private final TopoVertex dst;
+
+    /**
+     * Creates a new topology edge.
+     *
+     * @param src  source vertex
+     * @param dst  destination vertex
+     * @param link infrastructure link
+     */
+    DefaultTopoEdge(TopoVertex src, TopoVertex dst, Link link) {
+        this.src = src;
+        this.dst = dst;
+        this.link = link;
+    }
+
+    @Override
+    public Link link() {
+        return link;
+    }
+
+    @Override
+    public TopoVertex src() {
+        return src;
+    }
+
+    @Override
+    public TopoVertex dst() {
+        return dst;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(link);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof DefaultTopoEdge) {
+            final DefaultTopoEdge other = (DefaultTopoEdge) obj;
+            return Objects.equals(this.link, other.link);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this).add("src", src).add("dst", dst).toString();
+    }
+
+}
+
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/DefaultTopoVertex.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/DefaultTopoVertex.java
new file mode 100644
index 0000000..afcaca6
--- /dev/null
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/DefaultTopoVertex.java
@@ -0,0 +1,49 @@
+package org.onlab.onos.net.trivial.topology.provider.impl;
+
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.topology.TopoVertex;
+
+import java.util.Objects;
+
+/**
+ * Implementation of the topology vertex backed by a device id.
+ */
+class DefaultTopoVertex implements TopoVertex {
+
+    private final DeviceId deviceId;
+
+    /**
+     * Creates a new topology vertex.
+     *
+     * @param deviceId backing infrastructure device identifier
+     */
+    DefaultTopoVertex(DeviceId deviceId) {
+        this.deviceId = deviceId;
+    }
+
+    @Override
+    public DeviceId deviceId() {
+        return deviceId;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(deviceId);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof DefaultTopoVertex) {
+            final DefaultTopoVertex other = (DefaultTopoVertex) obj;
+            return Objects.equals(this.deviceId, other.deviceId);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return deviceId.toString();
+    }
+
+}
+
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/DefaultTopologyDescription.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/DefaultTopologyDescription.java
new file mode 100644
index 0000000..408e6af
--- /dev/null
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/DefaultTopologyDescription.java
@@ -0,0 +1,247 @@
+package org.onlab.onos.net.trivial.topology.provider.impl;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.ImmutableSetMultimap;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+import org.onlab.graph.AdjacencyListsGraph;
+import org.onlab.graph.DijkstraGraphSearch;
+import org.onlab.graph.Graph;
+import org.onlab.graph.GraphPathSearch;
+import org.onlab.graph.TarjanGraphSearch;
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.Device;
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.topology.ClusterId;
+import org.onlab.onos.net.topology.DefaultTopologyCluster;
+import org.onlab.onos.net.topology.LinkWeight;
+import org.onlab.onos.net.topology.TopoEdge;
+import org.onlab.onos.net.topology.TopoVertex;
+import org.onlab.onos.net.topology.TopologyCluster;
+import org.onlab.onos.net.topology.TopologyDescription;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static com.google.common.collect.ImmutableSetMultimap.Builder;
+import static org.onlab.graph.GraphPathSearch.Result;
+import static org.onlab.graph.TarjanGraphSearch.SCCResult;
+import static org.onlab.onos.net.Link.Type.INDIRECT;
+
+/**
+ * Default implementation of an immutable topology data carrier.
+ */
+class DefaultTopologyDescription implements TopologyDescription {
+
+    private static final GraphPathSearch<TopoVertex, TopoEdge> DIJKSTRA =
+            new DijkstraGraphSearch<>();
+    private static final TarjanGraphSearch<TopoVertex, TopoEdge> TARJAN =
+            new TarjanGraphSearch<>();
+
+    private final long nanos;
+    private final Map<DeviceId, TopoVertex> vertexesById = Maps.newHashMap();
+    private final Graph<TopoVertex, TopoEdge> graph;
+    private final Map<DeviceId, Result<TopoVertex, TopoEdge>> results;
+    private final Map<ClusterId, TopologyCluster> clusters;
+
+    // Secondary look-up indexes
+    private ImmutableSetMultimap<ClusterId, DeviceId> devicesByCluster;
+    private ImmutableSetMultimap<ClusterId, Link> linksByCluster;
+    private Map<DeviceId, TopologyCluster> clustersByDevice = Maps.newHashMap();
+
+    /**
+     * Creates a topology description to carry topology vitals to the core.
+     *
+     * @param nanos   time in nanos of when the topology description was created
+     * @param devices collection of infrastructure devices
+     * @param links   collection of infrastructure links
+     */
+    DefaultTopologyDescription(long nanos, Iterable<Device> devices, Iterable<Link> links) {
+        this.nanos = nanos;
+        this.graph = buildGraph(devices, links);
+        this.results = computeDefaultPaths();
+        this.clusters = computeClusters();
+    }
+
+    @Override
+    public long timestamp() {
+        return nanos;
+    }
+
+    @Override
+    public Graph<TopoVertex, TopoEdge> graph() {
+        return graph;
+    }
+
+    @Override
+    public Result<TopoVertex, TopoEdge> pathResults(DeviceId srcDeviceId) {
+        return results.get(srcDeviceId);
+    }
+
+    @Override
+    public Set<TopologyCluster> clusters() {
+        return ImmutableSet.copyOf(clusters.values());
+    }
+
+    @Override
+    public Set<DeviceId> clusterDevices(TopologyCluster cluster) {
+        return devicesByCluster.get(cluster.id());
+    }
+
+    @Override
+    public Set<Link> clusterLinks(TopologyCluster cluster) {
+        return linksByCluster.get(cluster.id());
+    }
+
+    @Override
+    public TopologyCluster clusterFor(DeviceId deviceId) {
+        return clustersByDevice.get(deviceId);
+    }
+
+
+    // 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(TopoEdge edge) {
+            // To force preference to use direct paths first, make indirect
+            // links as expensive as the linear vertex traversal.
+            return edge.link().type() == INDIRECT ? indirectLinkCost : 1;
+        }
+    }
+
+    // Link weight for preventing traversal over indirect links.
+    private static class NoIndirectLinksWeight implements LinkWeight {
+        @Override
+        public double weight(TopoEdge edge) {
+            return edge.link().type() == INDIRECT ? -1 : 1;
+        }
+    }
+
+    // Constructs the topology graph using the supplied devices and links.
+    private Graph<TopoVertex, TopoEdge> buildGraph(Iterable<Device> devices,
+                                                   Iterable<Link> links) {
+        return new AdjacencyListsGraph<>(buildVertexes(devices),
+                                         buildEdges(links));
+    }
+
+    // Builds a set of topology vertexes from the specified list of devices
+    private Set<TopoVertex> buildVertexes(Iterable<Device> devices) {
+        Set<TopoVertex> vertexes = Sets.newHashSet();
+        for (Device device : devices) {
+            TopoVertex vertex = new DefaultTopoVertex(device.id());
+            vertexes.add(vertex);
+            vertexesById.put(vertex.deviceId(), vertex);
+        }
+        return vertexes;
+    }
+
+    // Builds a set of topology vertexes from the specified list of links
+    private Set<TopoEdge> buildEdges(Iterable<Link> links) {
+        Set<TopoEdge> edges = Sets.newHashSet();
+        for (Link link : links) {
+            edges.add(new DefaultTopoEdge(vertexOf(link.src()),
+                                          vertexOf(link.dst()), link));
+        }
+        return edges;
+    }
+
+    // Computes the default shortest paths for all source/dest pairs using
+    // the multi-path Dijkstra and hop-count as path cost.
+    private Map<DeviceId, Result<TopoVertex, TopoEdge>> computeDefaultPaths() {
+        LinkWeight weight = new HopCountLinkWeight(graph.getVertexes().size());
+        Map<DeviceId, Result<TopoVertex, TopoEdge>> results = Maps.newHashMap();
+
+        // Search graph paths for each source to all destinations.
+        for (TopoVertex src : vertexesById.values()) {
+            results.put(src.deviceId(), DIJKSTRA.search(graph, src, null, weight));
+        }
+        return results;
+    }
+
+    // Computes topology SCC clusters using Tarjan algorithm.
+    private Map<ClusterId, TopologyCluster> computeClusters() {
+        Map<ClusterId, TopologyCluster> clusters = Maps.newHashMap();
+        SCCResult<TopoVertex, TopoEdge> result = TARJAN.search(graph, new NoIndirectLinksWeight());
+
+        // Extract both vertexes and edges from the results; the lists form
+        // pairs along the same index.
+        List<Set<TopoVertex>> clusterVertexes = result.clusterVertexes();
+        List<Set<TopoEdge>> clusterEdges = result.clusterEdges();
+
+        Builder<ClusterId, DeviceId> devicesBuilder = ImmutableSetMultimap.builder();
+        Builder<ClusterId, Link> linksBuilder = ImmutableSetMultimap.builder();
+
+        // Scan over the lists and create a cluster from the results.
+        for (int i = 0, n = result.clusterCount(); i < n; i++) {
+            Set<TopoVertex> vertexSet = clusterVertexes.get(i);
+            Set<TopoEdge> edgeSet = clusterEdges.get(i);
+
+            DefaultTopologyCluster cluster =
+                    new DefaultTopologyCluster(ClusterId.clusterId(i),
+                                               vertexSet.size(), edgeSet.size(),
+                                               findRoot(vertexSet).deviceId());
+            findClusterDevices(vertexSet, cluster, devicesBuilder);
+            findClusterLinks(edgeSet, cluster, linksBuilder);
+        }
+        return clusters;
+    }
+
+    // Scans through the set of cluster vertexes and puts their devices in a
+    // multi-map associated with the cluster. It also binds the devices to
+    // the cluster.
+    private void findClusterDevices(Set<TopoVertex> vertexSet,
+                                    DefaultTopologyCluster cluster,
+                                    Builder<ClusterId, DeviceId> builder) {
+        for (TopoVertex vertex : vertexSet) {
+            DeviceId deviceId = vertex.deviceId();
+            builder.put(cluster.id(), deviceId);
+            clustersByDevice.put(deviceId, cluster);
+        }
+    }
+
+    // Scans through the set of cluster edges and puts their links in a
+    // multi-map associated with the cluster.
+    private void findClusterLinks(Set<TopoEdge> edgeSet,
+                                  DefaultTopologyCluster cluster,
+                                  Builder<ClusterId, Link> builder) {
+        for (TopoEdge edge : edgeSet) {
+            builder.put(cluster.id(), edge.link());
+        }
+    }
+
+    // Finds the vertex whose device id is the lexicographical minimum in the
+    // specified set.
+    private TopoVertex findRoot(Set<TopoVertex> vertexSet) {
+        TopoVertex minVertex = null;
+        for (TopoVertex vertex : vertexSet) {
+            if (minVertex == null ||
+                    minVertex.deviceId().toString()
+                            .compareTo(minVertex.deviceId().toString()) < 0) {
+                minVertex = vertex;
+            }
+        }
+        return minVertex;
+    }
+
+    // Fetches a vertex corresponding to the given connection point device.
+    private TopoVertex vertexOf(ConnectPoint connectPoint) {
+        DeviceId id = connectPoint.deviceId();
+        TopoVertex vertex = vertexesById.get(id);
+        if (vertex == null) {
+            // If vertex does not exist, create one and register it.
+            vertex = new DefaultTopoVertex(id);
+            vertexesById.put(id, vertex);
+        }
+        return vertex;
+    }
+
+}
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyProvider.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/SimpleTopologyProvider.java
similarity index 98%
rename from core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyProvider.java
rename to core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/SimpleTopologyProvider.java
index 0e9ea3d..777a0e4 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleTopologyProvider.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/provider/impl/SimpleTopologyProvider.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.net.trivial.impl;
+package org.onlab.onos.net.trivial.topology.provider.impl;
 
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
@@ -115,7 +115,6 @@
     // Builds the topology using the latest device and link information
     // and citing the specified events as reasons for the change.
     private void buildTopology(List<Event> reasons) {
-        log.info("YO! Computing topology");
         if (isStarted) {
             TopologyDescription desc =
                     new DefaultTopologyDescription(System.nanoTime(),
diff --git a/core/trivial/src/main/javadoc/org/onlab/onos/event/impl/package.html b/core/trivial/src/main/javadoc/org/onlab/onos/event/impl/package.html
index a22d62d..87f0d91 100644
--- a/core/trivial/src/main/javadoc/org/onlab/onos/event/impl/package.html
+++ b/core/trivial/src/main/javadoc/org/onlab/onos/event/impl/package.html
@@ -1,3 +1,3 @@
 <body>
-ONOS local event dispatching mechanism.
+Local event dispatching mechanism.
 </body>
\ No newline at end of file
diff --git a/core/trivial/src/main/javadoc/org/onlab/onos/impl/package.html b/core/trivial/src/main/javadoc/org/onlab/onos/impl/package.html
index 087085c..84500a8 100644
--- a/core/trivial/src/main/javadoc/org/onlab/onos/impl/package.html
+++ b/core/trivial/src/main/javadoc/org/onlab/onos/impl/package.html
@@ -1,3 +1,3 @@
 <body>
-ONOS Core infrastructure implementations.
+Core infrastructure implementations.
 </body>
\ No newline at end of file
diff --git a/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/device/impl/package.html b/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/device/impl/package.html
new file mode 100644
index 0000000..2195da2
--- /dev/null
+++ b/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/device/impl/package.html
@@ -0,0 +1,3 @@
+<body>
+Core subsystem for tracking infrastructure devices.
+</body>
\ No newline at end of file
diff --git a/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/host/impl/package.html b/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/host/impl/package.html
new file mode 100644
index 0000000..79f7bb0
--- /dev/null
+++ b/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/host/impl/package.html
@@ -0,0 +1,3 @@
+<body>
+Core subsystem for tracking edn-station hosts.
+</body>
\ No newline at end of file
diff --git a/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/impl/package.html b/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/impl/package.html
deleted file mode 100644
index ba285bd..0000000
--- a/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/impl/package.html
+++ /dev/null
@@ -1,3 +0,0 @@
-<body>
-ONOS core implementations.
-</body>
\ No newline at end of file
diff --git a/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/link/impl/package.html b/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/link/impl/package.html
new file mode 100644
index 0000000..5bba317
--- /dev/null
+++ b/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/link/impl/package.html
@@ -0,0 +1,3 @@
+<body>
+Core subsystem for tracking infrastructure links.
+</body>
\ No newline at end of file
diff --git a/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/topology/impl/package.html b/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/topology/impl/package.html
new file mode 100644
index 0000000..b4cca07
--- /dev/null
+++ b/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/topology/impl/package.html
@@ -0,0 +1,3 @@
+<body>
+Core subsystem for tracking consistent topology graph views.
+</body>
\ No newline at end of file
diff --git a/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/topology/provider/impl/package.html b/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/topology/provider/impl/package.html
new file mode 100644
index 0000000..ee67aa8
--- /dev/null
+++ b/core/trivial/src/main/javadoc/org/onlab/onos/net/trivial/topology/provider/impl/package.html
@@ -0,0 +1,3 @@
+<body>
+Built-in protocol-agnostic topology builder &amp; provider.
+</body>
\ No newline at end of file
diff --git a/core/trivial/src/test/java/org/onlab/onos/net/trivial/impl/TestEventDispatcher.java b/core/trivial/src/test/java/org/onlab/onos/event/impl/TestEventDispatcher.java
similarity index 94%
rename from core/trivial/src/test/java/org/onlab/onos/net/trivial/impl/TestEventDispatcher.java
rename to core/trivial/src/test/java/org/onlab/onos/event/impl/TestEventDispatcher.java
index 82f8be5..9eb3980 100644
--- a/core/trivial/src/test/java/org/onlab/onos/net/trivial/impl/TestEventDispatcher.java
+++ b/core/trivial/src/test/java/org/onlab/onos/event/impl/TestEventDispatcher.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.net.trivial.impl;
+package org.onlab.onos.event.impl;
 
 import org.onlab.onos.event.DefaultEventSinkRegistry;
 import org.onlab.onos.event.Event;
diff --git a/core/trivial/src/test/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManagerTest.java b/core/trivial/src/test/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceManagerTest.java
similarity index 98%
rename from core/trivial/src/test/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManagerTest.java
rename to core/trivial/src/test/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceManagerTest.java
index bcece2d..4c1aff4 100644
--- a/core/trivial/src/test/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManagerTest.java
+++ b/core/trivial/src/test/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceManagerTest.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.net.trivial.impl;
+package org.onlab.onos.net.trivial.device.impl;
 
 import org.junit.After;
 import org.junit.Before;
@@ -22,6 +22,7 @@
 import org.onlab.onos.net.device.PortDescription;
 import org.onlab.onos.net.provider.AbstractProvider;
 import org.onlab.onos.net.provider.ProviderId;
+import org.onlab.onos.event.impl.TestEventDispatcher;
 
 import java.util.ArrayList;
 import java.util.Iterator;
diff --git a/core/trivial/src/test/java/org/onlab/onos/net/trivial/impl/SimpleLinkManagerTest.java b/core/trivial/src/test/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkManagerTest.java
similarity index 98%
rename from core/trivial/src/test/java/org/onlab/onos/net/trivial/impl/SimpleLinkManagerTest.java
rename to core/trivial/src/test/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkManagerTest.java
index 8dd9e1d..6eace8f 100644
--- a/core/trivial/src/test/java/org/onlab/onos/net/trivial/impl/SimpleLinkManagerTest.java
+++ b/core/trivial/src/test/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkManagerTest.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.net.trivial.impl;
+package org.onlab.onos.net.trivial.link.impl;
 
 import com.google.common.collect.ImmutableSet;
 import org.junit.After;
@@ -21,6 +21,7 @@
 import org.onlab.onos.net.link.LinkService;
 import org.onlab.onos.net.provider.AbstractProvider;
 import org.onlab.onos.net.provider.ProviderId;
+import org.onlab.onos.event.impl.TestEventDispatcher;
 
 import java.util.ArrayList;
 import java.util.Iterator;
diff --git a/pom.xml b/pom.xml
index 3ec7f1c..1002901 100644
--- a/pom.xml
+++ b/pom.xml
@@ -332,7 +332,7 @@
                         <group>
                             <title>Core Subsystems</title>
                             <packages>
-                                org.onlab.onos.net.trivial.impl:org.onlab.onos.net.*.impl:org.onlab.onos.impl:org.onlab.onos.event.impl
+                                org.onlab.onos.net.trivial.*:org.onlab.onos.net.*.impl:org.onlab.onos.impl:org.onlab.onos.event.impl
                             </packages>
                         </group>
                         <group>
diff --git a/providers/of/link/src/main/java/org/onlab/onos/provider/of/link/impl/LinkDiscovery.java b/providers/of/link/src/main/java/org/onlab/onos/provider/of/link/impl/LinkDiscovery.java
index b0b86f0..da89681 100644
--- a/providers/of/link/src/main/java/org/onlab/onos/provider/of/link/impl/LinkDiscovery.java
+++ b/providers/of/link/src/main/java/org/onlab/onos/provider/of/link/impl/LinkDiscovery.java
@@ -42,7 +42,7 @@
 import org.onlab.packet.Ethernet;
 import org.onlab.packet.ONLabLddp;
 import org.onlab.packet.ONLabLddp.DPIDandPort;
-import org.onlab.timer.Timer;
+import org.onlab.util.Timer;
 import org.projectfloodlight.openflow.protocol.OFFactory;
 import org.projectfloodlight.openflow.protocol.OFMessage;
 import org.projectfloodlight.openflow.protocol.OFPacketOut;
diff --git a/providers/of/link/src/main/java/org/onlab/onos/provider/of/link/impl/OpenFlowLinkProvider.java b/providers/of/link/src/main/java/org/onlab/onos/provider/of/link/impl/OpenFlowLinkProvider.java
index b26d61c..218145d 100644
--- a/providers/of/link/src/main/java/org/onlab/onos/provider/of/link/impl/OpenFlowLinkProvider.java
+++ b/providers/of/link/src/main/java/org/onlab/onos/provider/of/link/impl/OpenFlowLinkProvider.java
@@ -1,10 +1,5 @@
 package org.onlab.onos.provider.of.link.impl;
 
-import static org.slf4j.LoggerFactory.getLogger;
-
-import java.util.Map;
-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;
@@ -28,6 +23,11 @@
 import org.projectfloodlight.openflow.protocol.OFPortStatus;
 import org.slf4j.Logger;
 
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import static org.slf4j.LoggerFactory.getLogger;
+
 /**
  * Provider which uses an OpenFlow controller to detect network
  * infrastructure links.
@@ -101,7 +101,7 @@
         @Override
         public void switchAdded(Dpid dpid) {
             discoverers.put(dpid, new LinkDiscovery(controller.getSwitch(dpid),
-                    controller, providerService, useBDDP));
+                                                    controller, providerService, useBDDP));
 
         }
 
diff --git a/utils/misc/src/main/java/org/onlab/timer/Timer.java b/utils/misc/src/main/java/org/onlab/timer/Timer.java
deleted file mode 100644
index 1f821a7..0000000
--- a/utils/misc/src/main/java/org/onlab/timer/Timer.java
+++ /dev/null
@@ -1,20 +0,0 @@
-package org.onlab.timer;
-
-import org.jboss.netty.util.HashedWheelTimer;
-
-
-public final class Timer {
-
-    private Timer() {}
-
-    private static HashedWheelTimer timer;
-
-    public static HashedWheelTimer getTimer() {
-        if (Timer.timer == null) {
-            Timer.timer = new HashedWheelTimer();
-            Timer.timer.start();
-        }
-        return Timer.timer;
-    }
-
-}
diff --git a/utils/misc/src/main/java/org/onlab/util/Timer.java b/utils/misc/src/main/java/org/onlab/util/Timer.java
new file mode 100644
index 0000000..276138f
--- /dev/null
+++ b/utils/misc/src/main/java/org/onlab/util/Timer.java
@@ -0,0 +1,30 @@
+package org.onlab.util;
+
+import org.jboss.netty.util.HashedWheelTimer;
+
+/**
+ * Hashed-wheel timer singleton. Care must be taken to shutdown the timer
+ * only when the VM is ready to exit.
+ */
+public final class Timer {
+
+    private static HashedWheelTimer timer;
+
+    // Ban public construction
+    private Timer() {
+    }
+
+    /**
+     * Returns the singleton hashed-wheel timer.
+     *
+     * @return hashed-wheel timer
+     */
+    public static HashedWheelTimer getTimer() {
+        if (Timer.timer == null) {
+            Timer.timer = new HashedWheelTimer();
+            Timer.timer.start();
+        }
+        return Timer.timer;
+    }
+
+}