diff --git a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/INetworkGraphListener.java b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/INetworkGraphListener.java
new file mode 100644
index 0000000..88806ef
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/INetworkGraphListener.java
@@ -0,0 +1,22 @@
+package net.onrc.onos.ofcontroller.networkgraph;
+
+/**
+ * Interface which needs to be implemented to receive Topology events from
+ * NetworkGraph
+ *
+ * TODO Should these interface hand over Event object or Object in NetworkGraph.
+ */
+public interface INetworkGraphListener {
+    public void putSwitchEvent(SwitchEvent switchEvent);
+    public void removeSwitchEvent(SwitchEvent switchEvent);
+
+    public void putPortEvent(PortEvent portEvent);
+    public void removePortEvent(PortEvent portEvent);
+
+    public void putLinkEvent(LinkEvent linkEvent);
+    public void removeLinkEvent(LinkEvent linkEvent);
+
+    public void putDeviceEvent(DeviceEvent deviceEvent);
+    public void removeDeviceEvent(DeviceEvent deviceEvent);
+
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/INetworkGraphService.java b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/INetworkGraphService.java
index 318c0f7..5d94f65 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/INetworkGraphService.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/INetworkGraphService.java
@@ -11,11 +11,14 @@
 	 * @return
 	 */
     public NetworkGraph getNetworkGraph();
-    
+
+    public void registerNetworkGraphListener(INetworkGraphListener listener);
+    public void deregisterNetworkGraphListener(INetworkGraphListener listener);
+
     /**
      * Allows a module to get a reference to the southbound interface to
      * the network graph.
-     * TODO Figure out how to hide the southbound interface from 
+     * TODO Figure out how to hide the southbound interface from
      * applications/modules that shouldn't touch it
      * @return
      */
diff --git a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/NetworkGraphImpl.java b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/NetworkGraphImpl.java
index 8b6faeb..ae71633 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/NetworkGraphImpl.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/NetworkGraphImpl.java
@@ -8,6 +8,7 @@
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.LinkedBlockingQueue;
 
 import net.onrc.onos.datagrid.IDatagridService;
@@ -50,11 +51,13 @@
 
     private final NetworkGraphDatastore datastore;
     private final IControllerRegistryService registryService;
+    private CopyOnWriteArrayList<INetworkGraphListener> networkGraphListeners;
 
-    public NetworkGraphImpl(IControllerRegistryService registryService) {
+    public NetworkGraphImpl(IControllerRegistryService registryService, CopyOnWriteArrayList<INetworkGraphListener> networkGraphListeners) {
 	super();
 	datastore = new NetworkGraphDatastore(this);
 	this.registryService = registryService;
+	this.networkGraphListeners = networkGraphListeners;
     }
 
     /**
@@ -571,7 +574,8 @@
 		putSwitch(switchEvent);
 	    }
 	    // TODO handle invariant violation
-	    // TODO trigger instance local topology event handler
+	    // trigger instance local topology event handler
+	    dispatchPutSwitchEvent(switchEvent);
 	}
 
 	@Override
@@ -580,7 +584,8 @@
 		removeSwitch(switchEvent);
 	    }
 	    // TODO handle invariant violation
-	    // TODO trigger instance local topology event handler
+	    // trigger instance local topology event handler
+	    dispatchRemoveSwitchEvent(switchEvent);
 	}
 
 	@Override
@@ -589,7 +594,8 @@
 		putPort(portEvent);
 	    }
 	    // TODO handle invariant violation
-	    // TODO trigger instance local topology event handler
+	    // trigger instance local topology event handler
+	    dispatchPutPortEvent(portEvent);
 	}
 
 	@Override
@@ -598,7 +604,8 @@
 		removePort(portEvent);
 	    }
 	    // TODO handle invariant violation
-	    // TODO trigger instance local topology event handler
+	    // trigger instance local topology event handler
+	    dispatchRemovePortEvent(portEvent);
 	}
 
 	@Override
@@ -607,7 +614,8 @@
 		putLink(linkEvent);
 	    }
 	    // TODO handle invariant violation
-	    // TODO trigger instance local topology event handler
+	    // trigger instance local topology event handler
+	    dispatchPutLinkEvent(linkEvent);
 	}
 
 	@Override
@@ -616,7 +624,8 @@
 		removeLink(linkEvent);
 	    }
 	    // TODO handle invariant violation
-	    // TODO trigger instance local topology event handler
+	    // trigger instance local topology event handler
+	    dispatchRemoveLinkEvent(linkEvent);
 	}
 
 	@Override
@@ -625,7 +634,8 @@
 		putDevice(deviceEvent);
 	    }
 	    // TODO handle invariant violation
-	    // TODO trigger instance local topology event handler
+	    // trigger instance local topology event handler
+	    dispatchPutDeviceEvent(deviceEvent);
 	}
 
 	@Override
@@ -634,7 +644,8 @@
 		removeDevice(deviceEvent);
 	    }
 	    // TODO handle invariant violation
-	    // TODO trigger instance local topology event handler
+	    // trigger instance local topology event handler
+	    dispatchRemoveDeviceEvent(deviceEvent);
 	}
 
 	/* ************************************************
@@ -1052,6 +1063,62 @@
 	    }
 	}
 
+	private void dispatchPutSwitchEvent(SwitchEvent switchEvent) {
+	    for (INetworkGraphListener listener : this.networkGraphListeners) {
+		// TODO Should copy before handing them over to listener
+		listener.putSwitchEvent(switchEvent);
+	    }
+	}
+
+	private void dispatchRemoveSwitchEvent(SwitchEvent switchEvent) {
+	    for (INetworkGraphListener listener : this.networkGraphListeners) {
+		// TODO Should copy before handing them over to listener
+		listener.removeSwitchEvent(switchEvent);
+	    }
+	}
+
+	private void dispatchPutPortEvent(PortEvent portEvent) {
+	    for (INetworkGraphListener listener : this.networkGraphListeners) {
+		// TODO Should copy before handing them over to listener
+		listener.putPortEvent(portEvent);
+	    }
+	}
+
+	private void dispatchRemovePortEvent(PortEvent portEvent) {
+	    for (INetworkGraphListener listener : this.networkGraphListeners) {
+		// TODO Should copy before handing them over to listener
+		listener.removePortEvent(portEvent);
+	    }
+	}
+
+	private void dispatchPutLinkEvent(LinkEvent linkEvent) {
+	    for (INetworkGraphListener listener : this.networkGraphListeners) {
+		// TODO Should copy before handing them over to listener
+		listener.putLinkEvent(linkEvent);
+	    }
+	}
+
+	private void dispatchRemoveLinkEvent(LinkEvent linkEvent) {
+	    for (INetworkGraphListener listener : this.networkGraphListeners) {
+		// TODO Should copy before handing them over to listener
+		listener.removeLinkEvent(linkEvent);
+	    }
+	}
+
+	private void dispatchPutDeviceEvent(DeviceEvent deviceEvent) {
+	    for (INetworkGraphListener listener : this.networkGraphListeners) {
+		// TODO Should copy before handing them over to listener
+		listener.putDeviceEvent(deviceEvent);;
+	    }
+	}
+
+	private void dispatchRemoveDeviceEvent(DeviceEvent deviceEvent) {
+	    for (INetworkGraphListener listener : this.networkGraphListeners) {
+		// TODO Should copy before handing them over to listener
+		listener.removeDeviceEvent(deviceEvent);
+	    }
+	}
+
 	private SwitchImpl getSwitchImpl(Switch sw) {
 	    if (sw instanceof SwitchImpl) {
 		return (SwitchImpl) sw;
diff --git a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/NetworkGraphModule.java b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/NetworkGraphModule.java
index 97fa4b5..80f0d0b 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/NetworkGraphModule.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/NetworkGraphModule.java
@@ -5,6 +5,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 import net.floodlightcontroller.core.module.FloodlightModuleContext;
 import net.floodlightcontroller.core.module.FloodlightModuleException;
@@ -25,6 +26,7 @@
 	private IDatagridService datagridService;
 	private IControllerRegistryService registryService;
 
+	private CopyOnWriteArrayList<INetworkGraphListener> networkGraphListeners;
 
 	private IRestApiService restApi;
 
@@ -61,7 +63,8 @@
 		datagridService = context.getServiceImpl(IDatagridService.class);
 		registryService = context.getServiceImpl(IControllerRegistryService.class);
 
-		networkGraph = new NetworkGraphImpl(registryService);
+		networkGraphListeners = new CopyOnWriteArrayList<>();
+		networkGraph = new NetworkGraphImpl(registryService, networkGraphListeners);
 		//southboundNetworkGraph = new NetworkGraphDatastore(networkGraph);
 	}
 
@@ -81,4 +84,14 @@
 		return networkGraph;
 	}
 
+	@Override
+	public void registerNetworkGraphListener(INetworkGraphListener listener) {
+	    networkGraphListeners.addIfAbsent(listener);
+	}
+
+	@Override
+	public void deregisterNetworkGraphListener(INetworkGraphListener listener) {
+	    networkGraphListeners.remove(listener);
+	}
+
 }