Added initial pieces for topology related notifications.
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java b/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java
index 405a3ee..e0da7a8 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java
@@ -1,11 +1,14 @@
 package net.onrc.onos.ofcontroller.util.serializers;
 
 import java.util.ArrayList;
+
 import com.esotericsoftware.kryo2.Kryo;
-import net.onrc.onos.ofcontroller.util.*;
 
 import net.floodlightcontroller.util.MACAddress;
 
+import net.onrc.onos.ofcontroller.util.*;
+import net.onrc.onos.ofcontroller.topology.TopologyElement;
+
 /**
  * Class factory for allocating Kryo instances for
  * serialization/deserialization of classes.
@@ -81,6 +84,8 @@
 	// kryo.setReferences(false);
 	//
 	kryo.register(ArrayList.class);
+
+	// FlowPath and related classes
 	kryo.register(CallerId.class);
 	kryo.register(DataPath.class);
 	kryo.register(DataPathEndpoints.class);
@@ -117,6 +122,9 @@
 	kryo.register(Switch.class);
 	kryo.register(SwitchPort.class);
 
+	// Topology-related classes
+	kryo.register(TopologyElement.class);
+
 	return kryo;
     }
 }