diff --git a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/Constants.java b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/Constants.java
index d06d3f2..20a4afa 100644
--- a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/Constants.java
+++ b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/Constants.java
@@ -65,4 +65,7 @@
     public static final boolean DEFAULT_DISABLE = false;
     public static final boolean DEFAULT_ENABLE = true;
 
+    public static final String VXLAN = "VXLAN";
+    public static final String VLAN = "VLAN";
+    public static final String FLAT = "FLAT";
 }