diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocol.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocol.java
index 56dba79..9a792bb 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocol.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocol.java
@@ -105,6 +105,7 @@
     private static final KryoNamespace DATABASE = KryoNamespace.newBuilder()
             .register(ReadRequest.class)
             .register(WriteRequest.class)
+            .register(WriteRequest.Type.class)
             .register(InternalReadResult.class)
             .register(InternalWriteResult.class)
             .register(InternalReadResult.Status.class)
@@ -135,6 +136,7 @@
                     byte[].class)
             .build();
 
+    // serializer used for CopyCat Protocol
     public static final KryoSerializer SERIALIZER = new KryoSerializer() {
         @Override
         protected void setupKryoPool() {