diff --git a/core/net/src/main/java/org/onlab/onos/net/intent/impl/FlowTracker.java b/core/net/src/main/java/org/onlab/onos/net/intent/impl/FlowTracker.java
new file mode 100644
index 0000000..8f4a5c7
--- /dev/null
+++ b/core/net/src/main/java/org/onlab/onos/net/intent/impl/FlowTracker.java
@@ -0,0 +1,130 @@
+package org.onlab.onos.net.intent.impl;
+
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.SetMultimap;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.onos.event.Event;
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.LinkKey;
+import org.onlab.onos.net.intent.IntentId;
+import org.onlab.onos.net.link.LinkEvent;
+import org.onlab.onos.net.topology.TopologyEvent;
+import org.onlab.onos.net.topology.TopologyListener;
+import org.onlab.onos.net.topology.TopologyService;
+import org.slf4j.Logger;
+
+import java.util.Collection;
+import java.util.concurrent.ExecutorService;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.collect.Multimaps.synchronizedSetMultimap;
+import static java.util.concurrent.Executors.newSingleThreadExecutor;
+import static org.onlab.util.Tools.namedThreads;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Entity responsible for tracking installed flows and for monitoring topology
+ * events to determine what flows are affected by topology changes.
+ */
+@Component
+@Service
+public class FlowTracker implements FlowTrackerService {
+
+    private final Logger log = getLogger(getClass());
+
+    private final SetMultimap<LinkKey, IntentId> intentsByLink =
+            synchronizedSetMultimap(HashMultimap.<LinkKey, IntentId>create());
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected TopologyService topologyService;
+
+    private ExecutorService executorService =
+            newSingleThreadExecutor(namedThreads("onos-flowtracker"));
+
+    private TopologyListener listener = new InternalTopologyListener();
+    private TopologyChangeDelegate delegate;
+
+    @Activate
+    public void activate() {
+        topologyService.addListener(listener);
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        topologyService.removeListener(listener);
+        log.info("Stopped");
+    }
+
+    @Override
+    public void setDelegate(TopologyChangeDelegate delegate) {
+        checkNotNull(delegate, "Delegate cannot be null");
+        checkArgument(this.delegate == null || this.delegate == delegate,
+                      "Another delegate already set");
+        this.delegate = delegate;
+    }
+
+    @Override
+    public void unsetDelegate(TopologyChangeDelegate delegate) {
+        checkArgument(this.delegate == delegate, "Not the current delegate");
+        this.delegate = null;
+    }
+
+    @Override
+    public void addTrackedResources(IntentId intentId, Collection<Link> resources) {
+        for (Link link : resources) {
+            intentsByLink.put(new LinkKey(link), intentId);
+        }
+    }
+
+    @Override
+    public void removeTrackedResources(IntentId intentId, Collection<Link> resources) {
+        for (Link link : resources) {
+            intentsByLink.remove(new LinkKey(link), intentId);
+        }
+    }
+
+    // Internal re-actor to topology change events.
+    private class InternalTopologyListener implements TopologyListener {
+        @Override
+        public void event(TopologyEvent event) {
+            executorService.execute(new TopologyChangeHandler(event));
+        }
+    }
+
+    // Re-dispatcher of topology change events.
+    private class TopologyChangeHandler implements Runnable {
+
+        private final TopologyEvent event;
+
+        TopologyChangeHandler(TopologyEvent event) {
+            this.event = event;
+        }
+
+        @Override
+        public void run() {
+            if (event.reasons() == null) {
+                delegate.bumpIntents(intentsByLink.values());
+            } else {
+                for (Event reason : event.reasons()) {
+                    if (reason instanceof LinkEvent) {
+                        LinkEvent linkEvent = (LinkEvent) reason;
+                        if (linkEvent.type() == LinkEvent.Type.LINK_ADDED ||
+                                linkEvent.type() == LinkEvent.Type.LINK_UPDATED) {
+                            delegate.bumpIntents(intentsByLink.get(new LinkKey(linkEvent.subject())));
+                        } else if (linkEvent.type() == LinkEvent.Type.LINK_REMOVED) {
+                            delegate.failIntents(intentsByLink.get(new LinkKey(linkEvent.subject())));
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+}