diff --git a/lib/neutron_plugins/ml2 b/lib/neutron_plugins/ml2
index e429714..d798929 100644
--- a/lib/neutron_plugins/ml2
+++ b/lib/neutron_plugins/ml2
@@ -105,7 +105,7 @@
             if [[ -n "$PHYSICAL_NETWORK" ]]; then
                 Q_ML2_PLUGIN_FLAT_TYPE_OPTIONS+="${PHYSICAL_NETWORK},"
             fi
-            if [[ -n "$PUBLIC_PHYSICAL_NETWORK" ]]; then
+            if [[ -n "$PUBLIC_PHYSICAL_NETWORK" ]] && [[ "${PHYSICAL_NETWORK}" != "$PUBLIC_PHYSICAL_NETWORK" ]]; then
                 Q_ML2_PLUGIN_FLAT_TYPE_OPTIONS+="${PUBLIC_PHYSICAL_NETWORK},"
             fi
         fi