Added default link description & model entities.
diff --git a/net/api/src/main/java/org/onlab/onos/net/link/LinkDescription.java b/net/api/src/main/java/org/onlab/onos/net/link/LinkDescription.java
index 8d712f0..83af07c 100644
--- a/net/api/src/main/java/org/onlab/onos/net/link/LinkDescription.java
+++ b/net/api/src/main/java/org/onlab/onos/net/link/LinkDescription.java
@@ -1,17 +1,25 @@
package org.onlab.onos.net.link;
+import org.onlab.onos.net.ConnectPoint;
+
/**
* Describes an infrastructure link.
*/
public interface LinkDescription {
- // TODO: src, dst connection points, which are pairs of (DeviceId, PortNumber)
+ /**
+ * Returns the link source.
+ *
+ * @return links source
+ */
+ ConnectPoint src();
-// On the north:
-// Link = (ConnectPoint src, ConnectPoint dst);
-// ConnectPoint = (DeviceId, PortNumber);
+ /**
+ * Returns the link destination.
+ *
+ * @return links destination
+ */
+ ConnectPoint dst();
-// On the south
-// LinkDescription ~ Link
-
+ // Add further link attributes
}