diff --git a/core/api/src/main/java/org/onlab/onos/net/device/DefaultPortDescription.java b/core/api/src/main/java/org/onlab/onos/net/device/DefaultPortDescription.java
index eb75ede..e1dcf9e 100644
--- a/core/api/src/main/java/org/onlab/onos/net/device/DefaultPortDescription.java
+++ b/core/api/src/main/java/org/onlab/onos/net/device/DefaultPortDescription.java
@@ -48,4 +48,9 @@
         return isEnabled;
     }
 
+    // default constructor for serialization
+    private DefaultPortDescription() {
+        this.number = null;
+        this.isEnabled = false;
+    }
 }