diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/InternalPortStatusEvent.java b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/InternalPortStatusEvent.java
index 0bdfdbf..7d3854b 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/InternalPortStatusEvent.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/InternalPortStatusEvent.java
@@ -35,4 +35,11 @@
     public Timestamped<PortDescription> portDescription() {
         return portDescription;
     }
+
+    // for serializer
+    protected InternalPortStatusEvent() {
+        this.providerId = null;
+        this.deviceId = null;
+        this.portDescription = null;
+    }
 }