diff --git a/netopeer/voltha-transapi/voltha.yin b/netopeer/voltha-transapi/voltha.yin
index ca836ab..a30ddb6 100644
--- a/netopeer/voltha-transapi/voltha.yin
+++ b/netopeer/voltha-transapi/voltha.yin
@@ -1,3 +1,18 @@
+<!--
+Copyright 2017-present Open Networking Foundation
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
 <?xml version="1.0" encoding="UTF-8"?>
 <module xmlns="urn:ietf:params:xml:ns:yang:yin:1" xmlns:voltha="urn:opencord:params:xml:ns:voltha:voltha" name="voltha">
   <namespace uri="urn:opencord:params:xml:ns:voltha:voltha"/>