lldp discovery independent of OF

Change-Id: I720f727f6628e30e5d732e6d7bf742d1b7050812
diff --git a/core/api/src/main/java/org/onlab/onos/net/Device.java b/core/api/src/main/java/org/onlab/onos/net/Device.java
index 9e6018e..0294d99 100644
--- a/core/api/src/main/java/org/onlab/onos/net/Device.java
+++ b/core/api/src/main/java/org/onlab/onos/net/Device.java
@@ -1,5 +1,7 @@
 package org.onlab.onos.net;
 
+import org.onlab.packet.ChassisId;
+
 /**
  * Representation of a network infrastructure device.
  */
@@ -54,6 +56,13 @@
      */
     String serialNumber();
 
+    /**
+     * Returns the device chassis id.
+     *
+     * @return chassis id
+     */
+    ChassisId chassisId();
+
     // Device realizedBy(); ?
 
     // ports are not provided directly, but rather via DeviceService.getPorts(Device device);