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);
+
+}