diff --git a/src/main/java/net/onrc/onos/core/util/Dpid.java b/src/main/java/net/onrc/onos/core/util/Dpid.java
index e157975..8e4e837 100644
--- a/src/main/java/net/onrc/onos/core/util/Dpid.java
+++ b/src/main/java/net/onrc/onos/core/util/Dpid.java
@@ -20,7 +20,7 @@
     /**
      * Default constructor.
      */
-    public Dpid() {
+    protected Dpid() {
         this.value = Dpid.UNKNOWN;
     }