diff --git a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/LinkEvent.java b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/LinkEvent.java
index d9342aa..81f9ba3 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/LinkEvent.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/LinkEvent.java
@@ -1,5 +1,7 @@
 package net.onrc.onos.ofcontroller.networkgraph;
 
+import java.nio.ByteBuffer;
+
 import net.onrc.onos.ofcontroller.networkgraph.PortEvent.SwitchPort;
 
 /**
@@ -33,4 +35,13 @@
 	return "[LinkEvent " + src + "->" + dst + "]";
     }
 
+    public static final int LINKID_BYTES = 2 + PortEvent.PORTID_BYTES * 2;
+
+    public static byte[] getLinkID(Long src_dpid, Long src_port_no,
+	    Long dst_dpid, Long dst_port_no) {
+	return ByteBuffer.allocate(LinkEvent.LINKID_BYTES).putChar('L')
+		.put(PortEvent.getPortID(src_dpid, src_port_no))
+		.put(PortEvent.getPortID(dst_dpid, dst_port_no)).array();
+    }
+
 }