diff --git a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/Port.java b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/Port.java
index 8299022..453dd14 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/Port.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/Port.java
@@ -2,12 +2,19 @@
 
 
 
+/**
+ * Interface of Port Object exposed to the "NB" read-only Topology.
+ *
+ * Everything returned by these interfaces must be either Unmodifiable view,
+ * immutable object, or a copy of the original "SB" In-memory Topology.
+ *
+ */
 public interface Port {
 	public short getNumber();
 	public String getName();
 	public long getHardwareAddress();
-	
+
 	public Switch getSwitch();
-	
+
 	public Link getLink();
 }