VOL-955 Handling of port stats in OFAgent

Change-Id: Ib73bcb539dc573e577e5c9d736e425256c6a8972
diff --git a/ofagent/grpc_client.py b/ofagent/grpc_client.py
index 6d01015..af3ffe4 100644
--- a/ofagent/grpc_client.py
+++ b/ofagent/grpc_client.py
@@ -222,3 +222,10 @@
         res = yield threads.deferToThread(
             self.local_stub.ListLogicalDeviceFlowGroups, req)
         returnValue(res.items)
+
+    @inlineCallbacks
+    def list_ports(self, device_id):
+        req = ID(id=device_id)
+        res = yield threads.deferToThread(
+            self.local_stub.ListLogicalDevicePorts, req)
+        returnValue(res.items)
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