diff --git a/lib/neutron_plugins/services/l3 b/lib/neutron_plugins/services/l3
index 4ce87bd..2180099 100644
--- a/lib/neutron_plugins/services/l3
+++ b/lib/neutron_plugins/services/l3
@@ -15,6 +15,7 @@
 IPV6_PROVIDER_NETWORK_GATEWAY=${IPV6_PROVIDER_NETWORK_GATEWAY:-}
 
 PUBLIC_BRIDGE=${PUBLIC_BRIDGE:-br-ex}
+PUBLIC_BRIDGE_MTU=${PUBLIC_BRIDGE_MTU:-1500}
 
 # If Q_USE_PUBLIC_VETH=True, create and use a veth pair instead of
 # PUBLIC_BRIDGE.  This is intended to be used with