ONOS-745 Refactoring topology to compute only broadcast tree and not pre-compute paths.

ONOS-744 Refactoring graph search to allow requesting max number of paths.

Change-Id: I28467246b92df32ebb3155c45774ecc051fdd3dd

@@ -69,20 +69,18 @@ public class SummaryCommand extends AbstractShellCommand {
                     .put("links", topology.linkCount())
                     .put("links", topology.linkCount())
                     .put("hosts", get(HostService.class).getHostCount())
                     .put("hosts", get(HostService.class).getHostCount())
                     .put("SCC(s)", topology.clusterCount())
                     .put("SCC(s)", topology.clusterCount())
-                    .put("paths", topology.pathCount())
                     .put("flows", get(FlowRuleService.class).getFlowRuleCount())
                     .put("flows", get(FlowRuleService.class).getFlowRuleCount())
                     .put("intents", get(IntentService.class).getIntentCount()));
                     .put("intents", get(IntentService.class).getIntentCount()));
         } else {
         } else {
             print("node=%s, version=%s",
             print("node=%s, version=%s",
                   get(ClusterService.class).getLocalNode().ip(),
                   get(ClusterService.class).getLocalNode().ip(),
                   get(CoreService.class).version().toString());
                   get(CoreService.class).version().toString());
-            print("nodes=%d, devices=%d, links=%d, hosts=%d, SCC(s)=%s, paths=%d, flows=%d, intents=%d",
+            print("nodes=%d, devices=%d, links=%d, hosts=%d, SCC(s)=%s, flows=%d, intents=%d",
                   activeNodes(get(ClusterService.class).getNodes()),
                   activeNodes(get(ClusterService.class).getNodes()),
                   get(DeviceService.class).getDeviceCount(),
                   get(DeviceService.class).getDeviceCount(),
                   get(LinkService.class).getLinkCount(),
                   get(LinkService.class).getLinkCount(),
                   get(HostService.class).getHostCount(),
                   get(HostService.class).getHostCount(),
                   topologyService.getClusters(topology).size(),
                   topologyService.getClusters(topology).size(),
-                  topology.pathCount(),
                   get(FlowRuleService.class).getFlowRuleCount(),
                   get(FlowRuleService.class).getFlowRuleCount(),
                   get(IntentService.class).getIntentCount());
                   get(IntentService.class).getIntentCount());
         }
         }

@@ -31,7 +31,7 @@ import org.onosproject.net.topology.TopologyService;
 public class TopologyCommand extends AbstractShellCommand {
 public class TopologyCommand extends AbstractShellCommand {
 
 
     private static final String FMT =
     private static final String FMT =
-            "time=%s, devices=%d, links=%d, clusters=%d, paths=%d";
+            "time=%s, devices=%d, links=%d, clusters=%d";
 
 
     @Option(name = "-r", aliases = "--recompute", description = "Trigger topology re-computation",
     @Option(name = "-r", aliases = "--recompute", description = "Trigger topology re-computation",
             required = false, multiValued = false)
             required = false, multiValued = false)
@@ -59,11 +59,10 @@ public class TopologyCommand extends AbstractShellCommand {
                     .put("time", topology.time())
                     .put("time", topology.time())
                     .put("deviceCount", topology.deviceCount())
                     .put("deviceCount", topology.deviceCount())
                     .put("linkCount", topology.linkCount())
                     .put("linkCount", topology.linkCount())
-                    .put("clusterCount", topology.clusterCount())
-                    .put("pathCount", topology.pathCount()));
+                    .put("clusterCount", topology.clusterCount()));
         } else {
         } else {
             print(FMT, topology.time(), topology.deviceCount(), topology.linkCount(),
             print(FMT, topology.time(), topology.deviceCount(), topology.linkCount(),
-                  topology.clusterCount(), topology.pathCount());
+                  topology.clusterCount());
         }
         }
     }
     }
 
 

@@ -15,8 +15,6 @@
  */
  */
 package org.onosproject.net.topology;
 package org.onosproject.net.topology;
 
 
-import org.onosproject.net.DeviceId;
-
 import java.util.Objects;
 import java.util.Objects;
 
 
 import static com.google.common.base.MoreObjects.toStringHelper;
 import static com.google.common.base.MoreObjects.toStringHelper;
@@ -29,7 +27,7 @@ public class DefaultTopologyCluster implements TopologyCluster {
     private final ClusterId id;
     private final ClusterId id;
     private final int deviceCount;
     private final int deviceCount;
     private final int linkCount;
     private final int linkCount;
-    private final DeviceId root;
+    private final TopologyVertex root;
 
 
     /**
     /**
      * Creates a new topology cluster descriptor with the specified attributes.
      * Creates a new topology cluster descriptor with the specified attributes.
@@ -40,7 +38,7 @@ public class DefaultTopologyCluster implements TopologyCluster {
      * @param root        cluster root node
      * @param root        cluster root node
      */
      */
     public DefaultTopologyCluster(ClusterId id, int deviceCount, int linkCount,
     public DefaultTopologyCluster(ClusterId id, int deviceCount, int linkCount,
-                                  DeviceId root) {
+                                  TopologyVertex root) {
         this.id = id;
         this.id = id;
         this.deviceCount = deviceCount;
         this.deviceCount = deviceCount;
         this.linkCount = linkCount;
         this.linkCount = linkCount;
@@ -63,7 +61,7 @@ public class DefaultTopologyCluster implements TopologyCluster {
     }
     }
 
 
     @Override
     @Override
-    public DeviceId root() {
+    public TopologyVertex root() {
         return root;
         return root;
     }
     }
 
 

@@ -61,13 +61,4 @@ public interface Topology extends Provided {
      */
      */
     int linkCount();
     int linkCount();
 
 
-    /**
-     * Returns the number of infrastructure paths computed between devices
-     * in the topology. This means the number of all the shortest paths
-     * (hop-count) between all device pairs.
-     *
-     * @return number of paths
-     */
-    int pathCount();
-
 }
 }

@@ -15,8 +15,6 @@
  */
  */
 package org.onosproject.net.topology;
 package org.onosproject.net.topology;
 
 
-import org.onosproject.net.DeviceId;
-
 /**
 /**
  * Representation of an SCC (strongly-connected component) in a network topology.
  * Representation of an SCC (strongly-connected component) in a network topology.
  */
  */
@@ -44,10 +42,10 @@ public interface TopologyCluster {
     int linkCount();
     int linkCount();
 
 
     /**
     /**
-     * Returns the device identifier of the cluster root device.
+     * Returns the cluster root vertex.
      *
      *
-     * @return cluster root device identifier
+     * @return cluster root vertex
      */
      */
-    DeviceId root();
+    TopologyVertex root();
 
 
 }
 }

@@ -43,11 +43,12 @@ public class DefaultTopologyClusterTest {
         assertEquals("incorrect id", clusterId(6), cluster.id());
         assertEquals("incorrect id", clusterId(6), cluster.id());
         assertEquals("incorrect id", 5, cluster.deviceCount());
         assertEquals("incorrect id", 5, cluster.deviceCount());
         assertEquals("incorrect id", 4, cluster.linkCount());
         assertEquals("incorrect id", 4, cluster.linkCount());
-        assertEquals("incorrect id", deviceId("of:111"), cluster.root());
+        assertEquals("incorrect id", deviceId("of:111"), cluster.root().deviceId());
 
 
     }
     }
 
 
     private TopologyCluster cluster(int id, int dc, int lc, String root) {
     private TopologyCluster cluster(int id, int dc, int lc, String root) {
-        return new DefaultTopologyCluster(clusterId(id), dc, lc, deviceId(root));
+        return new DefaultTopologyCluster(clusterId(id), dc, lc,
+                                          new DefaultTopologyVertex(deviceId(root)));
     }
     }
 }
 }

@@ -31,7 +31,6 @@ import org.onosproject.net.topology.GraphDescription;
 import org.onosproject.net.topology.LinkWeight;
 import org.onosproject.net.topology.LinkWeight;
 import org.onosproject.net.topology.Topology;
 import org.onosproject.net.topology.Topology;
 import org.onosproject.net.topology.TopologyCluster;
 import org.onosproject.net.topology.TopologyCluster;
-import org.onosproject.net.topology.TopologyEdge;
 import org.onosproject.net.topology.TopologyEvent;
 import org.onosproject.net.topology.TopologyEvent;
 import org.onosproject.net.topology.TopologyGraph;
 import org.onosproject.net.topology.TopologyGraph;
 import org.onosproject.net.topology.TopologyListener;
 import org.onosproject.net.topology.TopologyListener;
@@ -127,7 +126,6 @@ public class TopologyManagerTest {
         assertEquals("wrong cluster count", 2, topology.clusterCount());
         assertEquals("wrong cluster count", 2, topology.clusterCount());
         assertEquals("wrong device count", 6, topology.deviceCount());
         assertEquals("wrong device count", 6, topology.deviceCount());
         assertEquals("wrong link count", 10, topology.linkCount());
         assertEquals("wrong link count", 10, topology.linkCount());
-        assertEquals("wrong path count", 18, topology.pathCount());
 
 
         assertEquals("wrong cluster count", 2, service.getClusters(topology).size());
         assertEquals("wrong cluster count", 2, service.getClusters(topology).size());
 
 
@@ -148,12 +146,6 @@ public class TopologyManagerTest {
         assertFalse("should not be infrastructure point",
         assertFalse("should not be infrastructure point",
                     service.isInfrastructure(topology, new ConnectPoint(did("a"), portNumber(3))));
                     service.isInfrastructure(topology, new ConnectPoint(did("a"), portNumber(3))));
 
 
-        // One of these cannot be a broadcast point... or we have a loop...
-//        assertFalse("should not be broadcast point",
-//                    service.isBroadcastPoint(topology, new ConnectPoint(did("a"), portNumber(1))) &&
-//                            service.isBroadcastPoint(topology, new ConnectPoint(did("b"), portNumber(1))) &&
-//                            service.isBroadcastPoint(topology, new ConnectPoint(did("c"), portNumber(1))) &&
-//                            service.isBroadcastPoint(topology, new ConnectPoint(did("d"), portNumber(1))));
         assertTrue("should be broadcast point",
         assertTrue("should be broadcast point",
                    service.isBroadcastPoint(topology, new ConnectPoint(did("a"), portNumber(3))));
                    service.isBroadcastPoint(topology, new ConnectPoint(did("a"), portNumber(3))));
     }
     }
@@ -182,12 +174,7 @@ public class TopologyManagerTest {
     public void onDemandPath() {
     public void onDemandPath() {
         submitTopologyGraph();
         submitTopologyGraph();
         Topology topology = service.currentTopology();
         Topology topology = service.currentTopology();
-        LinkWeight weight = new LinkWeight() {
-            @Override
-            public double weight(TopologyEdge edge) {
-                return 3.3;
-            }
-        };
+        LinkWeight weight = edge -> 3.3;
 
 
         Set<Path> paths = service.getPaths(topology, did("a"), did("c"), weight);
         Set<Path> paths = service.getPaths(topology, did("a"), did("c"), weight);
         assertEquals("wrong path count", 2, paths.size());
         assertEquals("wrong path count", 2, paths.size());

@@ -20,7 +20,6 @@ import com.google.common.base.Suppliers;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSetMultimap;
 import com.google.common.collect.ImmutableSetMultimap;
-
 import org.onlab.graph.DijkstraGraphSearch;
 import org.onlab.graph.DijkstraGraphSearch;
 import org.onlab.graph.GraphPathSearch;
 import org.onlab.graph.GraphPathSearch;
 import org.onlab.graph.GraphPathSearch.Result;
 import org.onlab.graph.GraphPathSearch.Result;
@@ -51,11 +50,13 @@ import java.util.Set;
 
 
 import static com.google.common.base.MoreObjects.toStringHelper;
 import static com.google.common.base.MoreObjects.toStringHelper;
 import static com.google.common.collect.ImmutableSetMultimap.Builder;
 import static com.google.common.collect.ImmutableSetMultimap.Builder;
+import static org.onlab.graph.GraphPathSearch.ALL_PATHS;
 import static org.onosproject.core.CoreService.CORE_PROVIDER_ID;
 import static org.onosproject.core.CoreService.CORE_PROVIDER_ID;
 import static org.onosproject.net.Link.State.ACTIVE;
 import static org.onosproject.net.Link.State.ACTIVE;
 import static org.onosproject.net.Link.State.INACTIVE;
 import static org.onosproject.net.Link.State.INACTIVE;
 import static org.onosproject.net.Link.Type.INDIRECT;
 import static org.onosproject.net.Link.Type.INDIRECT;
 
 
+// FIXME: Move to onos-core-common when ready
 /**
 /**
  * Default implementation of the topology descriptor. This carries the
  * Default implementation of the topology descriptor. This carries the
  * backing topology data.
  * backing topology data.
@@ -71,10 +72,8 @@ public class DefaultTopology extends AbstractModel implements Topology {
     private final long computeCost;
     private final long computeCost;
     private final TopologyGraph graph;
     private final TopologyGraph graph;
 
 
+    private final LinkWeight weight;
     private final Supplier<SCCResult<TopologyVertex, TopologyEdge>> clusterResults;
     private final Supplier<SCCResult<TopologyVertex, TopologyEdge>> clusterResults;
-    private final Supplier<ImmutableMap<DeviceId, Result<TopologyVertex, TopologyEdge>>> results;
-    private final Supplier<ImmutableSetMultimap<PathKey, Path>> paths;
-
     private final Supplier<ImmutableMap<ClusterId, TopologyCluster>> clusters;
     private final Supplier<ImmutableMap<ClusterId, TopologyCluster>> clusters;
     private final Supplier<ImmutableSet<ConnectPoint>> infrastructurePoints;
     private final Supplier<ImmutableSet<ConnectPoint>> infrastructurePoints;
     private final Supplier<ImmutableSetMultimap<ClusterId, ConnectPoint>> broadcastSets;
     private final Supplier<ImmutableSetMultimap<ClusterId, ConnectPoint>> broadcastSets;
@@ -95,15 +94,12 @@ public class DefaultTopology extends AbstractModel implements Topology {
         this.graph = new DefaultTopologyGraph(description.vertexes(),
         this.graph = new DefaultTopologyGraph(description.vertexes(),
                                               description.edges());
                                               description.edges());
 
 
-
-        this.results = Suppliers.memoize(() -> searchForShortestPaths());
-        this.paths = Suppliers.memoize(() -> buildPaths());
-
         this.clusterResults = Suppliers.memoize(() -> searchForClusters());
         this.clusterResults = Suppliers.memoize(() -> searchForClusters());
         this.clusters = Suppliers.memoize(() -> buildTopologyClusters());
         this.clusters = Suppliers.memoize(() -> buildTopologyClusters());
 
 
         this.clusterIndexes = Suppliers.memoize(() -> buildIndexes());
         this.clusterIndexes = Suppliers.memoize(() -> buildIndexes());
 
 
+        this.weight = new HopCountLinkWeight(graph.getVertexes().size());
         this.broadcastSets = Suppliers.memoize(() -> buildBroadcastSets());
         this.broadcastSets = Suppliers.memoize(() -> buildBroadcastSets());
         this.infrastructurePoints = Suppliers.memoize(() -> findInfrastructurePoints());
         this.infrastructurePoints = Suppliers.memoize(() -> findInfrastructurePoints());
         this.computeCost = Math.max(0, System.nanoTime() - time);
         this.computeCost = Math.max(0, System.nanoTime() - time);
@@ -134,11 +130,6 @@ public class DefaultTopology extends AbstractModel implements Topology {
         return graph.getEdges().size();
         return graph.getEdges().size();
     }
     }
 
 
-    @Override
-    public int pathCount() {
-        return paths.get().size();
-    }
-
     private ImmutableMap<DeviceId, TopologyCluster> clustersByDevice() {
     private ImmutableMap<DeviceId, TopologyCluster> clustersByDevice() {
         return clusterIndexes.get().clustersByDevice;
         return clusterIndexes.get().clustersByDevice;
     }
     }
@@ -262,7 +253,7 @@ public class DefaultTopology extends AbstractModel implements Topology {
      * @return set of shortest paths
      * @return set of shortest paths
      */
      */
     Set<Path> getPaths(DeviceId src, DeviceId dst) {
     Set<Path> getPaths(DeviceId src, DeviceId dst) {
-        return paths.get().get(new PathKey(src, dst));
+        return getPaths(src, dst, null);
     }
     }
 
 
     /**
     /**
@@ -284,7 +275,7 @@ public class DefaultTopology extends AbstractModel implements Topology {
         }
         }
 
 
         GraphPathSearch.Result<TopologyVertex, TopologyEdge> result =
         GraphPathSearch.Result<TopologyVertex, TopologyEdge> result =
-                DIJKSTRA.search(graph, srcV, dstV, weight);
+                DIJKSTRA.search(graph, srcV, dstV, weight, ALL_PATHS);
         ImmutableSet.Builder<Path> builder = ImmutableSet.builder();
         ImmutableSet.Builder<Path> builder = ImmutableSet.builder();
         for (org.onlab.graph.Path<TopologyVertex, TopologyEdge> path : result.paths()) {
         for (org.onlab.graph.Path<TopologyVertex, TopologyEdge> path : result.paths()) {
             builder.add(networkPath(path));
             builder.add(networkPath(path));
@@ -293,31 +284,6 @@ public class DefaultTopology extends AbstractModel implements Topology {
     }
     }
 
 
 
 
-    // Searches the graph for all shortest paths and returns the search results.
-    private ImmutableMap<DeviceId, Result<TopologyVertex, TopologyEdge>> searchForShortestPaths() {
-        ImmutableMap.Builder<DeviceId, Result<TopologyVertex, TopologyEdge>> builder = ImmutableMap.builder();
-
-        // Search graph paths for each source to all destinations.
-        LinkWeight weight = new HopCountLinkWeight(graph.getVertexes().size());
-        for (TopologyVertex src : graph.getVertexes()) {
-            builder.put(src.deviceId(), DIJKSTRA.search(graph, src, null, weight));
-        }
-        return builder.build();
-    }
-
-    // Builds network paths from the graph path search results
-    private ImmutableSetMultimap<PathKey, Path> buildPaths() {
-        Builder<PathKey, Path> builder = ImmutableSetMultimap.builder();
-        for (DeviceId deviceId : results.get().keySet()) {
-            Result<TopologyVertex, TopologyEdge> result = results.get().get(deviceId);
-            for (org.onlab.graph.Path<TopologyVertex, TopologyEdge> path : result.paths()) {
-                builder.put(new PathKey(path.src().deviceId(), path.dst().deviceId()),
-                            networkPath(path));
-            }
-        }
-        return builder.build();
-    }
-
     // Converts graph path to a network path with the same cost.
     // Converts graph path to a network path with the same cost.
     private Path networkPath(org.onlab.graph.Path<TopologyVertex, TopologyEdge> path) {
     private Path networkPath(org.onlab.graph.Path<TopologyVertex, TopologyEdge> path) {
         List<Link> links = new ArrayList<>();
         List<Link> links = new ArrayList<>();
@@ -337,23 +303,21 @@ public class DefaultTopology extends AbstractModel implements Topology {
     // Builds the topology clusters and returns the id-cluster bindings.
     // Builds the topology clusters and returns the id-cluster bindings.
     private ImmutableMap<ClusterId, TopologyCluster> buildTopologyClusters() {
     private ImmutableMap<ClusterId, TopologyCluster> buildTopologyClusters() {
         ImmutableMap.Builder<ClusterId, TopologyCluster> clusterBuilder = ImmutableMap.builder();
         ImmutableMap.Builder<ClusterId, TopologyCluster> clusterBuilder = ImmutableMap.builder();
-        SCCResult<TopologyVertex, TopologyEdge> result =
-                TARJAN.search(graph, new NoIndirectLinksWeight());
-
+        SCCResult<TopologyVertex, TopologyEdge> results = clusterResults.get();
         // Extract both vertexes and edges from the results; the lists form
         // Extract both vertexes and edges from the results; the lists form
         // pairs along the same index.
         // pairs along the same index.
-        List<Set<TopologyVertex>> clusterVertexes = result.clusterVertexes();
-        List<Set<TopologyEdge>> clusterEdges = result.clusterEdges();
+        List<Set<TopologyVertex>> clusterVertexes = results.clusterVertexes();
+        List<Set<TopologyEdge>> clusterEdges = results.clusterEdges();
 
 
         // Scan over the lists and create a cluster from the results.
         // Scan over the lists and create a cluster from the results.
-        for (int i = 0, n = result.clusterCount(); i < n; i++) {
+        for (int i = 0, n = results.clusterCount(); i < n; i++) {
             Set<TopologyVertex> vertexSet = clusterVertexes.get(i);
             Set<TopologyVertex> vertexSet = clusterVertexes.get(i);
             Set<TopologyEdge> edgeSet = clusterEdges.get(i);
             Set<TopologyEdge> edgeSet = clusterEdges.get(i);
 
 
             ClusterId cid = ClusterId.clusterId(i);
             ClusterId cid = ClusterId.clusterId(i);
             DefaultTopologyCluster cluster =
             DefaultTopologyCluster cluster =
                     new DefaultTopologyCluster(cid, vertexSet.size(), edgeSet.size(),
                     new DefaultTopologyCluster(cid, vertexSet.size(), edgeSet.size(),
-                                               findRoot(vertexSet).deviceId());
+                                               findRoot(vertexSet));
             clusterBuilder.put(cid, cluster);
             clusterBuilder.put(cid, cluster);
         }
         }
         return clusterBuilder.build();
         return clusterBuilder.build();
@@ -388,7 +352,8 @@ public class DefaultTopology extends AbstractModel implements Topology {
     private void addClusterBroadcastSet(TopologyCluster cluster,
     private void addClusterBroadcastSet(TopologyCluster cluster,
                                         Builder<ClusterId, ConnectPoint> builder) {
                                         Builder<ClusterId, ConnectPoint> builder) {
         // Use the graph root search results to build the broadcast set.
         // Use the graph root search results to build the broadcast set.
-        Result<TopologyVertex, TopologyEdge> result = results.get().get(cluster.root());
+        Result<TopologyVertex, TopologyEdge> result =
+                DIJKSTRA.search(graph, cluster.root(), null, weight, 1);
         for (Map.Entry<TopologyVertex, Set<TopologyEdge>> entry : result.parents().entrySet()) {
         for (Map.Entry<TopologyVertex, Set<TopologyEdge>> entry : result.parents().entrySet()) {
             TopologyVertex vertex = entry.getKey();
             TopologyVertex vertex = entry.getKey();
 
 
@@ -498,7 +463,6 @@ public class DefaultTopology extends AbstractModel implements Topology {
                 .add("clusters", clusterCount())
                 .add("clusters", clusterCount())
                 .add("devices", deviceCount())
                 .add("devices", deviceCount())
                 .add("links", linkCount())
                 .add("links", linkCount())
-                .add("pathCount", pathCount())
                 .toString();
                 .toString();
     }
     }
 }
 }

@@ -17,6 +17,7 @@ package org.onosproject.store.trivial.impl;
 
 
 import org.junit.Before;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.Test;
+import org.onlab.packet.ChassisId;
 import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.DefaultDevice;
 import org.onosproject.net.DefaultDevice;
 import org.onosproject.net.DefaultLink;
 import org.onosproject.net.DefaultLink;
@@ -31,8 +32,6 @@ import org.onosproject.net.topology.DefaultGraphDescription;
 import org.onosproject.net.topology.GraphDescription;
 import org.onosproject.net.topology.GraphDescription;
 import org.onosproject.net.topology.LinkWeight;
 import org.onosproject.net.topology.LinkWeight;
 import org.onosproject.net.topology.TopologyCluster;
 import org.onosproject.net.topology.TopologyCluster;
-import org.onosproject.net.topology.TopologyEdge;
-import org.onlab.packet.ChassisId;
 
 
 import java.util.Set;
 import java.util.Set;
 
 
@@ -57,13 +56,9 @@ public class DefaultTopologyTest {
     public static final PortNumber P1 = portNumber(1);
     public static final PortNumber P1 = portNumber(1);
     public static final PortNumber P2 = portNumber(2);
     public static final PortNumber P2 = portNumber(2);
 
 
-    public static final LinkWeight WEIGHT = new LinkWeight() {
-        @Override
-        public double weight(TopologyEdge edge) {
-            return edge.src().deviceId().equals(D4) ||
-                    edge.dst().deviceId().equals(D4) ? 2.0 : 1.0;
-        }
-    };
+    public static final LinkWeight WEIGHT = edge ->
+            edge.src().deviceId().equals(D4) || edge.dst().deviceId().equals(D4)
+                    ? 2.0 : 1.0;
 
 
     private DefaultTopology dt;
     private DefaultTopology dt;
 
 

@@ -65,17 +65,31 @@ public abstract class AbstractGraphPathSearch<V extends Vertex, E extends Edge<V
         protected final Set<Path<V, E>> paths = new HashSet<>();
         protected final Set<Path<V, E>> paths = new HashSet<>();
         protected final Map<V, Double> costs = new HashMap<>();
         protected final Map<V, Double> costs = new HashMap<>();
         protected final Map<V, Set<E>> parents = new HashMap<>();
         protected final Map<V, Set<E>> parents = new HashMap<>();
+        protected final int maxPaths;
 
 
         /**
         /**
-         * Creates the result of path search.
+         * Creates the result of a single-path search.
          *
          *
          * @param src path source
          * @param src path source
          * @param dst optional path destination
          * @param dst optional path destination
          */
          */
         public DefaultResult(V src, V dst) {
         public DefaultResult(V src, V dst) {
+            this(src, dst, 1);
+        }
+
+        /**
+         * Creates the result of path search.
+         *
+         * @param src      path source
+         * @param dst      optional path destination
+         * @param maxPaths optional limit of number of paths;
+         *                 {@link GraphPathSearch#ALL_PATHS} if no limit
+         */
+        public DefaultResult(V src, V dst, int maxPaths) {
             checkNotNull(src, "Source cannot be null");
             checkNotNull(src, "Source cannot be null");
             this.src = src;
             this.src = src;
             this.dst = dst;
             this.dst = dst;
+            this.maxPaths = maxPaths;
         }
         }
 
 
         @Override
         @Override
@@ -126,7 +140,8 @@ public abstract class AbstractGraphPathSearch<V extends Vertex, E extends Edge<V
 
 
         /**
         /**
          * Updates the cost of the vertex using its existing cost plus the
          * Updates the cost of the vertex using its existing cost plus the
-         * cost to traverse the specified edge.
+         * cost to traverse the specified edge. If the search is in single
+         * path mode, only one path will be accrued.
          *
          *
          * @param vertex  vertex to update
          * @param vertex  vertex to update
          * @param edge    edge through which vertex is reached
          * @param edge    edge through which vertex is reached
@@ -147,9 +162,11 @@ public abstract class AbstractGraphPathSearch<V extends Vertex, E extends Edge<V
                 if (replace) {
                 if (replace) {
                     edges.clear();
                     edges.clear();
                 }
                 }
+                if (maxPaths == ALL_PATHS || edges.size() < maxPaths) {
                     edges.add(edge);
                     edges.add(edge);
                 }
                 }
             }
             }
+        }
 
 
         /**
         /**
          * Removes the set of parent edges for the specified vertex.
          * Removes the set of parent edges for the specified vertex.
@@ -203,7 +220,7 @@ public abstract class AbstractGraphPathSearch<V extends Vertex, E extends Edge<V
             for (V v : destinations) {
             for (V v : destinations) {
                 // Ignore the source, if it is among the destinations.
                 // Ignore the source, if it is among the destinations.
                 if (!v.equals(src)) {
                 if (!v.equals(src)) {
-                    buildAllPaths(this, src, v);
+                    buildAllPaths(this, src, v, maxPaths);
                 }
                 }
             }
             }
         }
         }
@@ -218,15 +235,18 @@ public abstract class AbstractGraphPathSearch<V extends Vertex, E extends Edge<V
      * @param result   graph search result
      * @param result   graph search result
      * @param src      source vertex
      * @param src      source vertex
      * @param dst      destination vertex
      * @param dst      destination vertex
+     * @param maxPaths limit on the number of paths built;
+     *                 {@link GraphPathSearch#ALL_PATHS} if no limit
      */
      */
-    private void buildAllPaths(DefaultResult result, V src, V dst) {
+    private void buildAllPaths(DefaultResult result, V src, V dst, int maxPaths) {
         DefaultMutablePath<V, E> basePath = new DefaultMutablePath<>();
         DefaultMutablePath<V, E> basePath = new DefaultMutablePath<>();
         basePath.setCost(result.cost(dst));
         basePath.setCost(result.cost(dst));
 
 
         Set<DefaultMutablePath<V, E>> pendingPaths = new HashSet<>();
         Set<DefaultMutablePath<V, E>> pendingPaths = new HashSet<>();
         pendingPaths.add(basePath);
         pendingPaths.add(basePath);
 
 
-        while (!pendingPaths.isEmpty()) {
+        while (!pendingPaths.isEmpty() &&
+                (maxPaths == ALL_PATHS || result.paths.size() < maxPaths)) {
             Set<DefaultMutablePath<V, E>> frontier = new HashSet<>();
             Set<DefaultMutablePath<V, E>> frontier = new HashSet<>();
 
 
             for (DefaultMutablePath<V, E> path : pendingPaths) {
             for (DefaultMutablePath<V, E> path : pendingPaths) {

@@ -24,11 +24,11 @@ public class BellmanFordGraphSearch<V extends Vertex, E extends Edge<V>>
 
 
     @Override
     @Override
     public Result<V, E> search(Graph<V, E> graph, V src, V dst,
     public Result<V, E> search(Graph<V, E> graph, V src, V dst,
-                               EdgeWeight<V, E> weight) {
+                               EdgeWeight<V, E> weight, int maxPaths) {
         checkArguments(graph, src, dst);
         checkArguments(graph, src, dst);
 
 
         // Prepare the graph search result.
         // Prepare the graph search result.
-        DefaultResult result = new DefaultResult(src, dst);
+        DefaultResult result = new DefaultResult(src, dst, maxPaths);
 
 
         // The source vertex has cost 0, of course.
         // The source vertex has cost 0, of course.
         result.updateVertex(src, null, 0.0, true);
         result.updateVertex(src, null, 0.0, true);

@@ -26,11 +26,11 @@ public class BreadthFirstSearch<V extends Vertex, E extends Edge<V>>
 
 
     @Override
     @Override
     public Result<V, E> search(Graph<V, E> graph, V src, V dst,
     public Result<V, E> search(Graph<V, E> graph, V src, V dst,
-                               EdgeWeight<V, E> weight) {
+                               EdgeWeight<V, E> weight, int maxPaths) {
         checkArguments(graph, src, dst);
         checkArguments(graph, src, dst);
 
 
         // Prepare the graph result.
         // Prepare the graph result.
-        DefaultResult result = new DefaultResult(src, dst);
+        DefaultResult result = new DefaultResult(src, dst, maxPaths);
 
 
         // Setup the starting frontier with the source as the sole vertex.
         // Setup the starting frontier with the source as the sole vertex.
         Set<V> frontier = new HashSet<>();
         Set<V> frontier = new HashSet<>();

@@ -36,11 +36,11 @@ public class DepthFirstSearch<V extends Vertex, E extends Edge<V>>
 
 
     @Override
     @Override
     public SpanningTreeResult search(Graph<V, E> graph, V src, V dst,
     public SpanningTreeResult search(Graph<V, E> graph, V src, V dst,
-                                     EdgeWeight<V, E> weight) {
+                                     EdgeWeight<V, E> weight, int maxPaths) {
         checkArguments(graph, src, dst);
         checkArguments(graph, src, dst);
 
 
         // Prepare the search result.
         // Prepare the search result.
-        SpanningTreeResult result = new SpanningTreeResult(src, dst);
+        SpanningTreeResult result = new SpanningTreeResult(src, dst, maxPaths);
 
 
         // The source vertex has cost 0, of course.
         // The source vertex has cost 0, of course.
         result.updateVertex(src, null, 0.0, true);
         result.updateVertex(src, null, 0.0, true);
@@ -143,9 +143,10 @@ public class DepthFirstSearch<V extends Vertex, E extends Edge<V>>
          *
          *
          * @param src      search source
          * @param src      search source
          * @param dst      optional search destination
          * @param dst      optional search destination
+         * @param maxPaths limit on the number of paths
          */
          */
-        public SpanningTreeResult(V src, V dst) {
-            super(src, dst);
+        public SpanningTreeResult(V src, V dst, int maxPaths) {
+            super(src, dst, maxPaths);
         }
         }
 
 
         /**
         /**

@@ -28,12 +28,12 @@ public class DijkstraGraphSearch<V extends Vertex, E extends Edge<V>>
 
 
     @Override
     @Override
     public Result<V, E> search(Graph<V, E> graph, V src, V dst,
     public Result<V, E> search(Graph<V, E> graph, V src, V dst,
-                               EdgeWeight<V, E> weight) {
+                               EdgeWeight<V, E> weight, int maxPaths) {
         checkArguments(graph, src, dst);
         checkArguments(graph, src, dst);
 
 
         // Use the default result to remember cumulative costs and parent
         // Use the default result to remember cumulative costs and parent
         // edges to each each respective vertex.
         // edges to each each respective vertex.
-        DefaultResult result = new DefaultResult(src, dst);
+        DefaultResult result = new DefaultResult(src, dst, maxPaths);
 
 
         // Cost to reach the source vertex is 0 of course.
         // Cost to reach the source vertex is 0 of course.
         result.updateVertex(src, null, 0.0, false);
         result.updateVertex(src, null, 0.0, false);

@@ -26,6 +26,8 @@ import java.util.Set;
  */
  */
 public interface GraphPathSearch<V extends Vertex, E extends Edge<V>> {
 public interface GraphPathSearch<V extends Vertex, E extends Edge<V>> {
 
 
+    public static int ALL_PATHS = -1;
+
     /**
     /**
      * Abstraction of a path search result.
      * Abstraction of a path search result.
      */
      */
@@ -68,7 +70,7 @@ public interface GraphPathSearch<V extends Vertex, E extends Edge<V>> {
     }
     }
 
 
     /**
     /**
-     * Searches the specified graph.
+     * Searches the specified graph for paths between vertices.
      *
      *
      * @param graph    graph to be searched
      * @param graph    graph to be searched
      * @param src      optional source vertex
      * @param src      optional source vertex
@@ -76,8 +78,10 @@ public interface GraphPathSearch<V extends Vertex, E extends Edge<V>> {
      *                 destinations will be searched
      *                 destinations will be searched
      * @param weight   optional edge-weight; if null cost of each edge will be
      * @param weight   optional edge-weight; if null cost of each edge will be
      *                 assumed to be 1.0
      *                 assumed to be 1.0
+     * @param maxPaths limit on number of paths; {@link GraphPathSearch#ALL_PATHS} if no limit
      * @return search results
      * @return search results
      */
      */
-    Result<V, E> search(Graph<V, E> graph, V src, V dst, EdgeWeight<V, E> weight);
+    Result<V, E> search(Graph<V, E> graph, V src, V dst,
+                        EdgeWeight<V, E> weight, int maxPaths);
 
 
 }
 }

@@ -23,6 +23,8 @@ import java.util.List;
 //import java.util.PriorityQueue;
 //import java.util.PriorityQueue;
 import java.util.Set;
 import java.util.Set;
 
 
+import static org.onlab.graph.GraphPathSearch.ALL_PATHS;
+
 /**
 /**
  * K-shortest-path graph search algorithm capable of finding not just one,
  * K-shortest-path graph search algorithm capable of finding not just one,
  * but K shortest paths with ascending order between the source and destinations.
  * but K shortest paths with ascending order between the source and destinations.
@@ -137,7 +139,7 @@ public class KshortestPathSearch<V extends Vertex, E extends Edge<V>> {
     private List<E> searchShortestPath(Graph<V, E> graph, V src, V dst) {
     private List<E> searchShortestPath(Graph<V, E> graph, V src, V dst) {
         // Determine the shortest path from the source to the destination by using the Dijkstra algorithm.
         // Determine the shortest path from the source to the destination by using the Dijkstra algorithm.
         DijkstraGraphSearch dijkstraAlg = new DijkstraGraphSearch();
         DijkstraGraphSearch dijkstraAlg = new DijkstraGraphSearch();
-        Set<Path> paths =  dijkstraAlg.search(graph, src, dst, weight).paths();
+        Set<Path> paths =  dijkstraAlg.search(graph, src, dst, weight, ALL_PATHS).paths();
         Iterator<Path> itr = paths.iterator();
         Iterator<Path> itr = paths.iterator();
         if (!itr.hasNext()) {
         if (!itr.hasNext()) {
             return null;
             return null;

@@ -36,19 +36,19 @@ public abstract class AbstractGraphPathSearchTest extends GraphTest {
     public void noSuchSourceArgument() {
     public void noSuchSourceArgument() {
         graphSearch().search(new AdjacencyListsGraph<>(of(B, C),
         graphSearch().search(new AdjacencyListsGraph<>(of(B, C),
                                                        of(new TestEdge(B, C, 1))),
                                                        of(new TestEdge(B, C, 1))),
-                             A, H, weight);
+                             A, H, weight, 1);
     }
     }
 
 
     @Test(expected = NullPointerException.class)
     @Test(expected = NullPointerException.class)
     public void nullGraphArgument() {
     public void nullGraphArgument() {
-        graphSearch().search(null, A, H, weight);
+        graphSearch().search(null, A, H, weight, 1);
     }
     }
 
 
     @Test(expected = NullPointerException.class)
     @Test(expected = NullPointerException.class)
     public void nullSourceArgument() {
     public void nullSourceArgument() {
         graphSearch().search(new AdjacencyListsGraph<>(of(B, C),
         graphSearch().search(new AdjacencyListsGraph<>(of(B, C),
                                                        of(new TestEdge(B, C, 1))),
                                                        of(new TestEdge(B, C, 1))),
-                             null, H, weight);
+                             null, H, weight, 1);
     }
     }
 
 
     @Test
     @Test

@@ -21,6 +21,7 @@ import java.util.HashSet;
 import java.util.Set;
 import java.util.Set;
 
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertEquals;
+import static org.onlab.graph.GraphPathSearch.ALL_PATHS;
 
 
 /**
 /**
  * Test of the Bellman-Ford algorithm.
  * Test of the Bellman-Ford algorithm.
@@ -56,7 +57,7 @@ public class BellmanFordGraphSearchTest extends BreadthFirstSearchTest {
         graph = new AdjacencyListsGraph<>(vertexes, edges);
         graph = new AdjacencyListsGraph<>(vertexes, edges);
 
 
         GraphPathSearch<TestVertex, TestEdge> search = graphSearch();
         GraphPathSearch<TestVertex, TestEdge> search = graphSearch();
-        Set<Path<TestVertex, TestEdge>> paths = search.search(graph, A, H, weight).paths();
+        Set<Path<TestVertex, TestEdge>> paths = search.search(graph, A, H, weight, ALL_PATHS).paths();
         assertEquals("incorrect paths count", 1, paths.size());
         assertEquals("incorrect paths count", 1, paths.size());
 
 
         Path p = paths.iterator().next();
         Path p = paths.iterator().next();
@@ -65,10 +66,10 @@ public class BellmanFordGraphSearchTest extends BreadthFirstSearchTest {
         assertEquals("incorrect path length", 5, p.edges().size());
         assertEquals("incorrect path length", 5, p.edges().size());
         assertEquals("incorrect path cost", 5.0, p.cost(), 0.1);
         assertEquals("incorrect path cost", 5.0, p.cost(), 0.1);
 
 
-        paths = search.search(graph, A, G, weight).paths();
+        paths = search.search(graph, A, G, weight, ALL_PATHS).paths();
         assertEquals("incorrect paths count", 0, paths.size());
         assertEquals("incorrect paths count", 0, paths.size());
 
 
-        paths = search.search(graph, A, null, weight).paths();
+        paths = search.search(graph, A, null, weight, ALL_PATHS).paths();
         printPaths(paths);
         printPaths(paths);
         assertEquals("incorrect paths count", 6, paths.size());
         assertEquals("incorrect paths count", 6, paths.size());
     }
     }

@@ -20,6 +20,7 @@ import org.junit.Test;
 import java.util.Set;
 import java.util.Set;
 
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertEquals;
+import static org.onlab.graph.GraphPathSearch.ALL_PATHS;
 
 
 /**
 /**
  * Test of the BFS and similar path search algorithms.
  * Test of the BFS and similar path search algorithms.
@@ -47,7 +48,8 @@ public class BreadthFirstSearchTest extends AbstractGraphPathSearchTest {
         graph = new AdjacencyListsGraph<>(vertexes(), edges());
         graph = new AdjacencyListsGraph<>(vertexes(), edges());
 
 
         GraphPathSearch<TestVertex, TestEdge> search = graphSearch();
         GraphPathSearch<TestVertex, TestEdge> search = graphSearch();
-        Set<Path<TestVertex, TestEdge>> paths = search.search(graph, A, H, weight).paths();
+        Set<Path<TestVertex, TestEdge>> paths =
+                search.search(graph, A, H, weight, ALL_PATHS).paths();
         assertEquals("incorrect paths count", 1, paths.size());
         assertEquals("incorrect paths count", 1, paths.size());
 
 
         Path p = paths.iterator().next();
         Path p = paths.iterator().next();
@@ -56,7 +58,7 @@ public class BreadthFirstSearchTest extends AbstractGraphPathSearchTest {
         assertEquals("incorrect path length", pathLength, p.edges().size());
         assertEquals("incorrect path length", pathLength, p.edges().size());
         assertEquals("incorrect path cost", pathCost, p.cost(), 0.1);
         assertEquals("incorrect path cost", pathCost, p.cost(), 0.1);
 
 
-        paths = search.search(graph, A, null, weight).paths();
+        paths = search.search(graph, A, null, weight, ALL_PATHS).paths();
         printPaths(paths);
         printPaths(paths);
         assertEquals("incorrect paths count", pathCount, paths.size());
         assertEquals("incorrect paths count", pathCount, paths.size());
     }
     }
@@ -68,7 +70,7 @@ public class BreadthFirstSearchTest extends AbstractGraphPathSearchTest {
                                  EdgeWeight<TestVertex, TestEdge> weight,
                                  EdgeWeight<TestVertex, TestEdge> weight,
                                  int pathCount, double pathCost) {
                                  int pathCount, double pathCost) {
         GraphPathSearch.Result<TestVertex, TestEdge> result =
         GraphPathSearch.Result<TestVertex, TestEdge> result =
-                search.search(graph, src, dst, weight);
+                search.search(graph, src, dst, weight, ALL_PATHS);
         Set<Path<TestVertex, TestEdge>> paths = result.paths();
         Set<Path<TestVertex, TestEdge>> paths = result.paths();
         printPaths(paths);
         printPaths(paths);
         assertEquals("incorrect paths count", pathCount, paths.size());
         assertEquals("incorrect paths count", pathCount, paths.size());
@@ -78,4 +80,21 @@ public class BreadthFirstSearchTest extends AbstractGraphPathSearchTest {
         }
         }
     }
     }
 
 
+    // Executes the single-path search and validates its results.
+    protected void executeSinglePathSearch(GraphPathSearch<TestVertex, TestEdge> search,
+                                           Graph<TestVertex, TestEdge> graph,
+                                           TestVertex src, TestVertex dst,
+                                           EdgeWeight<TestVertex, TestEdge> weight,
+                                           int pathCount, double pathCost) {
+        GraphPathSearch.Result<TestVertex, TestEdge> result =
+                search.search(graph, src, dst, weight, 1);
+        Set<Path<TestVertex, TestEdge>> paths = result.paths();
+        printPaths(paths);
+        assertEquals("incorrect paths count", Math.min(pathCount, 1), paths.size());
+        if (pathCount > 0) {
+            Path<TestVertex, TestEdge> path = paths.iterator().next();
+            assertEquals("incorrect path cost", pathCost, path.cost(), 0.1);
+        }
+    }
+
 }
 }

@@ -22,6 +22,7 @@ import java.util.Set;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.assertTrue;
 import static org.onlab.graph.DepthFirstSearch.EdgeType;
 import static org.onlab.graph.DepthFirstSearch.EdgeType;
+import static org.onlab.graph.GraphPathSearch.ALL_PATHS;
 
 
 /**
 /**
  * Test of the DFS algorithm.
  * Test of the DFS algorithm.
@@ -52,7 +53,7 @@ public class DepthFirstSearchTest extends AbstractGraphPathSearchTest {
         DepthFirstSearch<TestVertex, TestEdge> search = graphSearch();
         DepthFirstSearch<TestVertex, TestEdge> search = graphSearch();
 
 
         DepthFirstSearch<TestVertex, TestEdge>.SpanningTreeResult result =
         DepthFirstSearch<TestVertex, TestEdge>.SpanningTreeResult result =
-                search.search(graph, A, H, weight);
+                search.search(graph, A, H, weight, 1);
         Set<Path<TestVertex, TestEdge>> paths = result.paths();
         Set<Path<TestVertex, TestEdge>> paths = result.paths();
         assertEquals("incorrect path count", 1, paths.size());
         assertEquals("incorrect path count", 1, paths.size());
 
 
@@ -77,7 +78,7 @@ public class DepthFirstSearchTest extends AbstractGraphPathSearchTest {
 
 
         // Perform narrow path search to a specific destination.
         // Perform narrow path search to a specific destination.
         DepthFirstSearch<TestVertex, TestEdge>.SpanningTreeResult result =
         DepthFirstSearch<TestVertex, TestEdge>.SpanningTreeResult result =
-                search.search(graph, A, null, weight);
+                search.search(graph, A, null, weight, ALL_PATHS);
         assertEquals("incorrect paths count", 7, result.paths().size());
         assertEquals("incorrect paths count", 7, result.paths().size());
 
 
         int[] types = new int[]{0, 0, 0, 0};
         int[] types = new int[]{0, 0, 0, 0};

@@ -55,16 +55,16 @@ public class DijkstraGraphSearchTest extends BreadthFirstSearchTest {
                                              new TestEdge(C, D, 1),
                                              new TestEdge(C, D, 1),
                                              new TestEdge(D, C, 1)));
                                              new TestEdge(D, C, 1)));
         GraphPathSearch<TestVertex, TestEdge> gs = graphSearch();
         GraphPathSearch<TestVertex, TestEdge> gs = graphSearch();
-        Set<Path<TestVertex, TestEdge>> paths = gs.search(graph, A, B, weight).paths();
+        Set<Path<TestVertex, TestEdge>> paths = gs.search(graph, A, B, weight, 1).paths();
         printPaths(paths);
         printPaths(paths);
         assertEquals("incorrect paths count", 1, paths.size());
         assertEquals("incorrect paths count", 1, paths.size());
         assertEquals("incorrect path cost", 1.0, paths.iterator().next().cost(), 0.1);
         assertEquals("incorrect path cost", 1.0, paths.iterator().next().cost(), 0.1);
 
 
-        paths = gs.search(graph, A, D, weight).paths();
+        paths = gs.search(graph, A, D, weight, 1).paths();
         printPaths(paths);
         printPaths(paths);
         assertEquals("incorrect paths count", 0, paths.size());
         assertEquals("incorrect paths count", 0, paths.size());
 
 
-        paths = gs.search(graph, A, null, weight).paths();
+        paths = gs.search(graph, A, null, weight, 1).paths();
         printPaths(paths);
         printPaths(paths);
         assertEquals("incorrect paths count", 1, paths.size());
         assertEquals("incorrect paths count", 1, paths.size());
         assertEquals("incorrect path cost", 1.0, paths.iterator().next().cost(), 0.1);
         assertEquals("incorrect path cost", 1.0, paths.iterator().next().cost(), 0.1);
@@ -78,6 +78,7 @@ public class DijkstraGraphSearchTest extends BreadthFirstSearchTest {
                                              new TestEdge(B, D, 1),
                                              new TestEdge(B, D, 1),
                                              new TestEdge(C, D, 1)));
                                              new TestEdge(C, D, 1)));
         executeSearch(graphSearch(), graph, A, D, weight, 2, 2.0);
         executeSearch(graphSearch(), graph, A, D, weight, 2, 2.0);
+        executeSinglePathSearch(graphSearch(), graph, A, D, weight, 1, 2.0);
     }
     }
 
 
     @Test
     @Test
@@ -93,6 +94,7 @@ public class DijkstraGraphSearchTest extends BreadthFirstSearchTest {
                                              new TestEdge(F, G, 1),
                                              new TestEdge(F, G, 1),
                                              new TestEdge(A, G, 4)));
                                              new TestEdge(A, G, 4)));
         executeSearch(graphSearch(), graph, A, G, weight, 5, 4.0);
         executeSearch(graphSearch(), graph, A, G, weight, 5, 4.0);
+        executeSinglePathSearch(graphSearch(), graph, A, G, weight, 1, 4.0);
     }
     }
 
 
     @Test
     @Test
@@ -106,6 +108,7 @@ public class DijkstraGraphSearchTest extends BreadthFirstSearchTest {
                                              new TestEdge(F, G, 1), new TestEdge(F, H, 1),
                                              new TestEdge(F, G, 1), new TestEdge(F, H, 1),
                                              new TestEdge(A, E, 3), new TestEdge(B, D, 1)));
                                              new TestEdge(A, E, 3), new TestEdge(B, D, 1)));
         executeSearch(graphSearch(), graph, A, E, weight, 3, 3.0);
         executeSearch(graphSearch(), graph, A, E, weight, 3, 3.0);
+        executeSinglePathSearch(graphSearch(), graph, A, E, weight, 1, 3.0);
     }
     }
 
 
     @Test
     @Test
@@ -123,6 +126,7 @@ public class DijkstraGraphSearchTest extends BreadthFirstSearchTest {
                                              new TestEdge(G, A, -5),
                                              new TestEdge(G, A, -5),
                                              new TestEdge(A, G, 4)));
                                              new TestEdge(A, G, 4)));
         executeSearch(graphSearch(), graph, A, G, weight, 3, 4.0);
         executeSearch(graphSearch(), graph, A, G, weight, 3, 4.0);
+        executeSinglePathSearch(graphSearch(), graph, A, G, weight, 1, 4.0);
     }
     }
 
 
     @Test
     @Test

@@ -454,7 +454,6 @@ public abstract class TopologyViewMessages {
                              new Prop("Links", format(topology.linkCount())),
                              new Prop("Links", format(topology.linkCount())),
                              new Prop("Hosts", format(hostService.getHostCount())),
                              new Prop("Hosts", format(hostService.getHostCount())),
                              new Prop("Topology SCCs", format(topology.clusterCount())),
                              new Prop("Topology SCCs", format(topology.clusterCount())),
-                             new Prop("Paths", format(topology.pathCount())),
                              new Separator(),
                              new Separator(),
                              new Prop("Intents", format(intentService.getIntentCount())),
                              new Prop("Intents", format(intentService.getIntentCount())),
                              new Prop("Flows", format(flowService.getFlowRuleCount())),
                              new Prop("Flows", format(flowService.getFlowRuleCount())),