diff --git a/core/api/src/main/java/org/onosproject/net/topology/AbstractPathService.java b/core/api/src/main/java/org/onosproject/net/topology/AbstractPathService.java
new file mode 100644
index 0000000..0292f70
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/topology/AbstractPathService.java
@@ -0,0 +1,255 @@
+/*
+ *
+ *  * Copyright 2016-present 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.net.topology;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DefaultDisjointPath;
+import org.onosproject.net.DefaultEdgeLink;
+import org.onosproject.net.DefaultPath;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.DisjointPath;
+import org.onosproject.net.EdgeLink;
+import org.onosproject.net.ElementId;
+import org.onosproject.net.Host;
+import org.onosproject.net.HostId;
+import org.onosproject.net.HostLocation;
+import org.onosproject.net.Link;
+import org.onosproject.net.Path;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.host.HostService;
+import org.onosproject.net.provider.ProviderId;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Helper class for path service.
+ */
+public abstract class AbstractPathService {
+
+    private static final String ELEMENT_ID_NULL = "Element ID cannot be null";
+    private static final EdgeLink NOT_HOST = new NotHost();
+
+    private static final ProviderId PID = new ProviderId("core", "org.onosproject.core");
+    private static final PortNumber P0 = PortNumber.portNumber(0);
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected TopologyService topologyService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected HostService hostService;
+
+    public Set<Path> getPaths(ElementId src, ElementId dst, LinkWeight weight) {
+        checkNotNull(src, ELEMENT_ID_NULL);
+        checkNotNull(dst, ELEMENT_ID_NULL);
+
+        // Get the source and destination edge locations
+        EdgeLink srcEdge = getEdgeLink(src, true);
+        EdgeLink dstEdge = getEdgeLink(dst, false);
+
+        // If either edge is null, bail with no paths.
+        if (srcEdge == null || dstEdge == null) {
+            return ImmutableSet.of();
+        }
+
+        DeviceId srcDevice = srcEdge != NOT_HOST ? srcEdge.dst().deviceId() : (DeviceId) src;
+        DeviceId dstDevice = dstEdge != NOT_HOST ? dstEdge.src().deviceId() : (DeviceId) dst;
+
+        // If the source and destination are on the same edge device, there
+        // is just one path, so build it and return it.
+        if (srcDevice.equals(dstDevice)) {
+            return edgeToEdgePaths(srcEdge, dstEdge);
+        }
+
+        // Otherwise get all paths between the source and destination edge
+        // devices.
+        Topology topology = topologyService.currentTopology();
+        Set<Path> paths = weight == null ?
+                topologyService.getPaths(topology, srcDevice, dstDevice) :
+                topologyService.getPaths(topology, srcDevice, dstDevice, weight);
+
+        return edgeToEdgePaths(srcEdge, dstEdge, paths);
+    }
+
+    public Set<DisjointPath> getDisjointPaths(ElementId src, ElementId dst, LinkWeight weight) {
+        checkNotNull(src, ELEMENT_ID_NULL);
+        checkNotNull(dst, ELEMENT_ID_NULL);
+
+        // Get the source and destination edge locations
+        EdgeLink srcEdge = getEdgeLink(src, true);
+        EdgeLink dstEdge = getEdgeLink(dst, false);
+
+        // If either edge is null, bail with no paths.
+        if (srcEdge == null || dstEdge == null) {
+            return ImmutableSet.of();
+        }
+
+        DeviceId srcDevice = srcEdge != NOT_HOST ? srcEdge.dst().deviceId() : (DeviceId) src;
+        DeviceId dstDevice = dstEdge != NOT_HOST ? dstEdge.src().deviceId() : (DeviceId) dst;
+
+        // If the source and destination are on the same edge device, there
+        // is just one path, so build it and return it.
+        if (srcDevice.equals(dstDevice)) {
+            return edgeToEdgePathsDisjoint(srcEdge, dstEdge);
+        }
+
+        // Otherwise get all paths between the source and destination edge
+        // devices.
+        Topology topology = topologyService.currentTopology();
+        Set<DisjointPath> paths = weight == null ?
+                topologyService.getDisjointPaths(topology, srcDevice, dstDevice) :
+                topologyService.getDisjointPaths(topology, srcDevice, dstDevice, weight);
+
+        return edgeToEdgePathsDisjoint(srcEdge, dstEdge, paths);
+    }
+
+    public Set<DisjointPath> getDisjointPaths(ElementId src, ElementId dst, LinkWeight weight,
+                                              Map<Link, Object> riskProfile) {
+        checkNotNull(src, ELEMENT_ID_NULL);
+        checkNotNull(dst, ELEMENT_ID_NULL);
+
+        // Get the source and destination edge locations
+        EdgeLink srcEdge = getEdgeLink(src, true);
+        EdgeLink dstEdge = getEdgeLink(dst, false);
+
+        // If either edge is null, bail with no paths.
+        if (srcEdge == null || dstEdge == null) {
+            return ImmutableSet.of();
+        }
+
+        DeviceId srcDevice = srcEdge != NOT_HOST ? srcEdge.dst().deviceId() : (DeviceId) src;
+        DeviceId dstDevice = dstEdge != NOT_HOST ? dstEdge.src().deviceId() : (DeviceId) dst;
+
+        // If the source and destination are on the same edge device, there
+        // is just one path, so build it and return it.
+        if (srcDevice.equals(dstDevice)) {
+            return edgeToEdgePathsDisjoint(srcEdge, dstEdge);
+        }
+
+        // Otherwise get all paths between the source and destination edge
+        // devices.
+        Topology topology = topologyService.currentTopology();
+        Set<DisjointPath> paths = weight == null ?
+                topologyService.getDisjointPaths(topology, srcDevice, dstDevice, riskProfile) :
+                topologyService.getDisjointPaths(topology, srcDevice, dstDevice, weight, riskProfile);
+
+        return edgeToEdgePathsDisjoint(srcEdge, dstEdge, paths);
+    }
+
+    // Finds the host edge link if the element ID is a host id of an existing
+    // host. Otherwise, if the host does not exist, it returns null and if
+    // the element ID is not a host ID, returns NOT_HOST edge link.
+    private EdgeLink getEdgeLink(ElementId elementId, boolean isIngress) {
+        if (elementId instanceof HostId) {
+            // Resolve the host, return null.
+            Host host = hostService.getHost((HostId) elementId);
+            if (host == null) {
+                return null;
+            }
+            return new DefaultEdgeLink(PID, new ConnectPoint(elementId, P0),
+                                       host.location(), isIngress);
+        }
+        return NOT_HOST;
+    }
+
+    // Produces a set of edge-to-edge paths using the set of infrastructure
+    // paths and the given edge links.
+    private Set<Path> edgeToEdgePaths(EdgeLink srcLink, EdgeLink dstLink) {
+        Set<Path> endToEndPaths = Sets.newHashSetWithExpectedSize(1);
+        endToEndPaths.add(edgeToEdgePath(srcLink, dstLink, null));
+        return endToEndPaths;
+    }
+
+    // Produces a set of edge-to-edge paths using the set of infrastructure
+    // paths and the given edge links.
+    private Set<Path> edgeToEdgePaths(EdgeLink srcLink, EdgeLink dstLink, Set<Path> paths) {
+        Set<Path> endToEndPaths = Sets.newHashSetWithExpectedSize(paths.size());
+        for (Path path : paths) {
+            endToEndPaths.add(edgeToEdgePath(srcLink, dstLink, path));
+        }
+        return endToEndPaths;
+    }
+
+    private Set<DisjointPath> edgeToEdgePathsDisjoint(EdgeLink srcLink, EdgeLink dstLink) {
+        Set<DisjointPath> endToEndPaths = Sets.newHashSetWithExpectedSize(1);
+        endToEndPaths.add(edgeToEdgePathD(srcLink, dstLink, null));
+        return endToEndPaths;
+    }
+
+    private Set<DisjointPath> edgeToEdgePathsDisjoint(EdgeLink srcLink, EdgeLink dstLink,
+                                                             Set<DisjointPath> paths) {
+        Set<DisjointPath> endToEndPaths = Sets.newHashSetWithExpectedSize(paths.size());
+        for (DisjointPath path : paths) {
+            endToEndPaths.add(edgeToEdgePathD(srcLink, dstLink, path));
+        }
+        return endToEndPaths;
+    }
+
+    // Produces a direct edge-to-edge path.
+    private Path edgeToEdgePath(EdgeLink srcLink, EdgeLink dstLink, Path path) {
+        List<Link> links = Lists.newArrayListWithCapacity(2);
+        double cost = 0;
+
+        // Add source and destination edge links only if they are real and
+        // add the infrastructure path only if it is not null.
+        if (srcLink != NOT_HOST) {
+            links.add(srcLink);
+            cost++;
+        }
+        if (path != null) {
+            links.addAll(path.links());
+            cost += path.cost();
+        }
+        if (dstLink != NOT_HOST) {
+            links.add(dstLink);
+            cost++;
+        }
+        return new DefaultPath(PID, links, cost);
+    }
+
+    // Produces a direct edge-to-edge path.
+    private DisjointPath edgeToEdgePathD(EdgeLink srcLink, EdgeLink dstLink, DisjointPath path) {
+        Path primary = null;
+        Path backup = null;
+        if (path != null) {
+            primary = path.primary();
+            backup = path.backup();
+        }
+        return new DefaultDisjointPath(PID, (DefaultPath) edgeToEdgePath(srcLink, dstLink, primary),
+                                       (DefaultPath) edgeToEdgePath(srcLink, dstLink, backup));
+    }
+
+
+    // Special value for edge link to represent that this is really not an
+    // edge link since the src or dst are really an infrastructure device.
+    private static class NotHost extends DefaultEdgeLink implements EdgeLink {
+        NotHost() {
+            super(PID, new ConnectPoint(HostId.NONE, P0),
+                  new HostLocation(DeviceId.NONE, P0, 0L), false);
+        }
+    }
+}