diff --git a/src/main/java/net/onrc/onos/core/topology/BaseInternalTopology.java b/src/main/java/net/onrc/onos/core/topology/BaseInternalTopology.java
index 6f9d9bf..cf44c32 100644
--- a/src/main/java/net/onrc/onos/core/topology/BaseInternalTopology.java
+++ b/src/main/java/net/onrc/onos/core/topology/BaseInternalTopology.java
@@ -11,7 +11,7 @@
 /**
  * Interface to reference internal self-contained elements.
  */
-public interface BaseInternalTopology {
+public interface BaseInternalTopology extends BaseMastership {
 
     /**
      * Gets a SwitchEvent.