Added more event and listener interface definitions.
diff --git a/net/api/src/main/java/org/onlab/onos/net/ConnectPoint.java b/net/api/src/main/java/org/onlab/onos/net/ConnectPoint.java
new file mode 100644
index 0000000..72ea3f4
--- /dev/null
+++ b/net/api/src/main/java/org/onlab/onos/net/ConnectPoint.java
@@ -0,0 +1,23 @@
+package org.onlab.onos.net;
+
+/**
+ * Abstraction of a network connection point expressed as a pair of the
+ * device identifier and the device port number.
+ */
+public interface ConnectPoint {
+
+ /**
+ * Returns the connection device identifier.
+ *
+ * @return device id
+ */
+ DeviceId deviceId();
+
+ /**
+ * Returns the connection port number.
+ *
+ * @return port number
+ */
+ PortNumber port();
+
+}