[ONOS-7269] Additional annotation about OpenFlow port status

Change-Id: I9a1b3cede47316c372322af68dc652d4f372f9fb
diff --git a/core/api/src/main/java/org/onosproject/net/AnnotationKeys.java b/core/api/src/main/java/org/onosproject/net/AnnotationKeys.java
index da93417..550899b 100644
--- a/core/api/src/main/java/org/onosproject/net/AnnotationKeys.java
+++ b/core/api/src/main/java/org/onosproject/net/AnnotationKeys.java
@@ -137,6 +137,13 @@
     public static final String PORT_MAC = "portMac";
 
     /**
+     * Annotation key for the admin state.
+     * The value of this key is expected to be "enabled" or "disabled"
+     *
+     */
+    public static final String ADMIN_STATE = "adminState";
+
+    /**
      * Annotation key for the router ID.
      */
     public static final String ROUTER_ID = "routerId";