Add OTN device and ports

Change-Id: I18f3376d1466077e95d7324a27a660302f0123b3
diff --git a/core/api/src/main/java/org/onosproject/net/OtuSignalType.java b/core/api/src/main/java/org/onosproject/net/OtuSignalType.java
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+++ b/core/api/src/main/java/org/onosproject/net/OtuSignalType.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * 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.
+ */
+
+package org.onosproject.net;
+
+/**
+ * Represents OTU (Optical channel Transport Unit) signal type.
+ *
+ * <p>
+ * See ITU G.709 "Interfaces for the Optical Transport Network (OTN)" and
+ * Open Networking Foundation "Optical Transport Protocol Extensions Version 1.0".
+ * </p>
+ */
+public enum OtuSignalType {
+    OTU1,
+    OTU2,
+    OTU3,
+    OTU4
+}
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