diff --git a/src/main/java/net/onrc/onos/graph/GraphDBConnection.java b/src/main/java/net/onrc/onos/graph/GraphDBConnection.java
index 53235ab..1e00668 100644
--- a/src/main/java/net/onrc/onos/graph/GraphDBConnection.java
+++ b/src/main/java/net/onrc/onos/graph/GraphDBConnection.java
@@ -63,6 +63,9 @@
 			if (!s.contains("dpid")) {
 				graph.createKeyIndex("dpid", Vertex.class);
 			}
+			if (!s.contains("port_id")) {
+				graph.createKeyIndex("port_id", Vertex.class);
+			}
 			if (!s.contains("type")) {
 				graph.createKeyIndex("type", Vertex.class);
 			}