ONOS core changes for RIP support

Change-Id: I5aa22ed6509d99af22d7cb80944bc3a4c26b5257
diff --git a/utils/misc/src/main/java/org/onlab/packet/Ip6Address.java b/utils/misc/src/main/java/org/onlab/packet/Ip6Address.java
index ecddc3a..085ecfc 100644
--- a/utils/misc/src/main/java/org/onlab/packet/Ip6Address.java
+++ b/utils/misc/src/main/java/org/onlab/packet/Ip6Address.java
@@ -45,6 +45,12 @@
             Ip6Address.valueOf("ff05::1:3");
 
     /**
+     * All RIP routers multicast group. (RFC 2080)
+     */
+    public static final Ip6Address ALL_RIP_ROUTERS =
+            Ip6Address.valueOf("ff02::9");
+
+    /**
      * All-zero unspecified IPv6 address.
      */
     public static final Ip6Address ZERO = Ip6Address.valueOf("::");