Change "type" constant name

Change-Id: Ia8a070d5d1937b68c0e77be3741c5d8f47748e4c
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyElement.java b/src/main/java/net/onrc/onos/core/topology/TopologyElement.java
index fc94c0a..685bc98 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyElement.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyElement.java
@@ -28,11 +28,11 @@
     /**
      * Attribute "type" value representing that the object belongs to Packet layer.
      */
-    public static final String TYPE_PACKET = "packet";
+    public static final String TYPE_PACKET_LAYER = "packet";
     /**
      * Attribute "type" value representing that the object belongs to Optical layer.
      */
-    public static final String TYPE_OPTICAL = "optical";
+    public static final String TYPE_OPTICAL_LAYER = "optical";
 
 
     private boolean isFrozen = false;
@@ -169,6 +169,6 @@
 
     @Override
     public String getType() {
-        return getStringAttribute(TYPE, TYPE_PACKET);
+        return getStringAttribute(TYPE, TYPE_PACKET_LAYER);
     }
 }