[ONOS-7752] check east-west VM reachability for troubleshoot purpose

Change-Id: I2922f5bc185a76906da5f12e4d18e640b9ecd8d8
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackNetworkManager.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackNetworkManager.java
index 3ca0232..2418745 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackNetworkManager.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackNetworkManager.java
@@ -641,6 +641,15 @@
                 .findAny().orElse(null);
     }
 
+    @Override
+    public String segmentId(String netId) {
+        Network network = network(netId);
+
+        checkNotNull(network);
+
+        return network.getProviderSegID();
+    }
+
     private boolean isNetworkInUse(String netId) {
         return !subnets(netId).isEmpty() && !ports(netId).isEmpty();
     }