diff --git a/src/main/java/net/onrc/onos/core/topology/DeviceImpl.java b/src/main/java/net/onrc/onos/core/topology/DeviceImpl.java
index f331b49..3c46656 100644
--- a/src/main/java/net/onrc/onos/core/topology/DeviceImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/DeviceImpl.java
@@ -133,6 +133,6 @@
     @Override
     public String getType() {
         // FIXME assuming device is always in packet layer for now.
-        return TopologyElement.TYPE_PACKET;
+        return TopologyElement.TYPE_PACKET_LAYER;
     }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/LinkImpl.java b/src/main/java/net/onrc/onos/core/topology/LinkImpl.java
index a573540..fce965a 100644
--- a/src/main/java/net/onrc/onos/core/topology/LinkImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/LinkImpl.java
@@ -174,6 +174,6 @@
      */
     @Override
     public String getType() {
-        return getStringAttribute(TopologyElement.TYPE, TopologyElement.TYPE_PACKET);
+        return getStringAttribute(TopologyElement.TYPE, TopologyElement.TYPE_PACKET_LAYER);
     }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/PortImpl.java b/src/main/java/net/onrc/onos/core/topology/PortImpl.java
index f022438..c1bb75c 100644
--- a/src/main/java/net/onrc/onos/core/topology/PortImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/PortImpl.java
@@ -246,6 +246,6 @@
      */
     @Override
     public String getType() {
-        return getStringAttribute(TopologyElement.TYPE, TopologyElement.TYPE_PACKET);
+        return getStringAttribute(TopologyElement.TYPE, TopologyElement.TYPE_PACKET_LAYER);
     }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/SwitchImpl.java b/src/main/java/net/onrc/onos/core/topology/SwitchImpl.java
index f434e33..3e2b9aa 100644
--- a/src/main/java/net/onrc/onos/core/topology/SwitchImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/SwitchImpl.java
@@ -199,6 +199,6 @@
      */
     @Override
     public String getType() {
-        return getStringAttribute(TopologyElement.TYPE, TopologyElement.TYPE_PACKET);
+        return getStringAttribute(TopologyElement.TYPE, TopologyElement.TYPE_PACKET_LAYER);
     }
 }
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);
     }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyImpl.java b/src/main/java/net/onrc/onos/core/topology/TopologyImpl.java
index e6e6763..81f3041 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyImpl.java
@@ -157,7 +157,7 @@
             return null;
         }
 
-        Link link = links.get(TopologyElement.TYPE_PACKET);
+        Link link = links.get(TopologyElement.TYPE_PACKET_LAYER);
         if (link != null) {
             // return packet link
             return link;
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyPublisher.java b/src/main/java/net/onrc/onos/core/topology/TopologyPublisher.java
index b82c86f..5e2b192 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyPublisher.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyPublisher.java
@@ -142,7 +142,7 @@
         // TODO define attr name as constant somewhere.
         // TODO populate appropriate attributes.
         linkEvent.createStringAttribute(TopologyElement.TYPE,
-                                        TopologyElement.TYPE_PACKET);
+                                        TopologyElement.TYPE_PACKET_LAYER);
 
         linkEvent.freeze();
 
@@ -166,7 +166,7 @@
         // TODO define attr name as constant somewhere.
         // TODO populate appropriate attributes.
         linkEvent.createStringAttribute(TopologyElement.TYPE,
-                                        TopologyElement.TYPE_PACKET);
+                                        TopologyElement.TYPE_PACKET_LAYER);
         linkEvent.freeze();
 
         if (!registryService.hasControl(link.getDst())) {
@@ -187,7 +187,7 @@
         // TODO define attr name as constant somewhere.
         // TODO populate appropriate attributes.
         portEvent.createStringAttribute(TopologyElement.TYPE,
-                                        TopologyElement.TYPE_PACKET);
+                                        TopologyElement.TYPE_PACKET_LAYER);
         portEvent.createStringAttribute("name", port.getName());
 
         portEvent.freeze();
@@ -210,7 +210,7 @@
         // TODO define attr name as constant somewhere.
         // TODO populate appropriate attributes.
         portEvent.createStringAttribute(TopologyElement.TYPE,
-                                        TopologyElement.TYPE_PACKET);
+                                        TopologyElement.TYPE_PACKET_LAYER);
         portEvent.createStringAttribute("name", port.getName());
 
         portEvent.freeze();
@@ -231,7 +231,7 @@
         // TODO define attr name as constant somewhere.
         // TODO populate appropriate attributes.
         switchEvent.createStringAttribute(TopologyElement.TYPE,
-                                          TopologyElement.TYPE_PACKET);
+                                          TopologyElement.TYPE_PACKET_LAYER);
         switchEvent.createStringAttribute("ConnectedSince",
                 sw.getConnectedSince().toString());
 
@@ -252,7 +252,7 @@
             // TODO populate appropriate attributes.
             portEvent.createStringAttribute("name", port.getName());
             portEvent.createStringAttribute(TopologyElement.TYPE,
-                                            TopologyElement.TYPE_PACKET);
+                                            TopologyElement.TYPE_PACKET_LAYER);
 
             portEvent.freeze();
             portEvents.add(portEvent);