Adding model abstractions to help flesh-out the concepts.
diff --git a/net/api/src/main/java/org/onlab/onos/net/Link.java b/net/api/src/main/java/org/onlab/onos/net/Link.java
index 200f682..75e026d 100644
--- a/net/api/src/main/java/org/onlab/onos/net/Link.java
+++ b/net/api/src/main/java/org/onlab/onos/net/Link.java
@@ -5,7 +5,8 @@
 /**
  * Abstraction of a network infrastructure link.
  */
-public interface Link extends Provided { // TODO: Also should extend graph Edge once the graph module is checked in
+public interface Link extends Provided {
+// TODO: Consider extending graph Edge<Element> once the graph module is available
 
     /**
      * Coarse representation of the link type.