diff --git a/lib/neutron_plugins/services/l3 b/lib/neutron_plugins/services/l3
index 61b8402..a4e7248 100644
--- a/lib/neutron_plugins/services/l3
+++ b/lib/neutron_plugins/services/l3
@@ -306,10 +306,15 @@
         if is_neutron_ovs_base_plugin; then
             ext_gw_interface=$(_neutron_get_ext_gw_interface)
         elif [[ "$Q_AGENT" = "linuxbridge" ]]; then
-            # Search for the brq device the neutron router and network for $FIXED_RANGE
+            # Get the device the neutron router and network for $FIXED_RANGE
             # will be using.
-            # e.x. brq3592e767-da for NET_ID 3592e767-da66-4bcb-9bec-cdb03cd96102
-            ext_gw_interface=brq${EXT_NET_ID:0:11}
+            if [ "$Q_USE_PROVIDERNET_FOR_PUBLIC" = "True" ]; then
+                # in provider nets a bridge mapping uses the public bridge directly
+                ext_gw_interface=$PUBLIC_BRIDGE
+            else
+                # e.x. brq3592e767-da for NET_ID 3592e767-da66-4bcb-9bec-cdb03cd96102
+                ext_gw_interface=brq${EXT_NET_ID:0:11}
+            fi
         fi
         if [[ "$ext_gw_interface" != "none" ]]; then
             local cidr_len=${FLOATING_RANGE#*/}