diff --git a/lib/neutron-legacy b/lib/neutron-legacy
index a08778ca32..5681743e41 100644
--- a/lib/neutron-legacy
+++ b/lib/neutron-legacy
@@ -168,6 +168,10 @@ NEUTRON_CREATE_INITIAL_NETWORKS=${NEUTRON_CREATE_INITIAL_NETWORKS:-True}
 ## Provider Network Information
 PROVIDER_SUBNET_NAME=${PROVIDER_SUBNET_NAME:-"provider_net"}
 
+# Define the public bridge that will transmit traffic from VMs to the
+# physical network - used by both the OVS and Linux Bridge drivers.
+PUBLIC_BRIDGE=${PUBLIC_BRIDGE:-br-ex}
+
 # Use flat providernet for public network
 #
 # If Q_USE_PROVIDERNET_FOR_PUBLIC=True, use a flat provider network
diff --git a/lib/neutron_plugins/linuxbridge_agent b/lib/neutron_plugins/linuxbridge_agent
index c9ea1cac28..b348af9c4f 100644
--- a/lib/neutron_plugins/linuxbridge_agent
+++ b/lib/neutron_plugins/linuxbridge_agent
@@ -7,6 +7,10 @@
 PLUGIN_XTRACE=$(set +o | grep xtrace)
 set +o xtrace
 
+function neutron_lb_cleanup {
+    sudo brctl delbr $PUBLIC_BRIDGE
+}
+
 function is_neutron_ovs_base_plugin {
     # linuxbridge doesn't use OVS
     return 1
@@ -29,6 +33,7 @@ function neutron_plugin_configure_dhcp_agent {
 }
 
 function neutron_plugin_configure_l3_agent {
+    sudo brctl addbr $PUBLIC_BRIDGE
     iniset $Q_L3_CONF_FILE DEFAULT external_network_bridge
     iniset $Q_L3_CONF_FILE DEFAULT l3_agent_manager neutron.agent.l3_agent.L3NATAgentWithStateReport
 }
diff --git a/lib/neutron_plugins/ovs_base b/lib/neutron_plugins/ovs_base
index 51999c60e4..81561d3114 100644
--- a/lib/neutron_plugins/ovs_base
+++ b/lib/neutron_plugins/ovs_base
@@ -8,7 +8,6 @@ OVSB_XTRACE=$(set +o | grep xtrace)
 set +o xtrace
 
 OVS_BRIDGE=${OVS_BRIDGE:-br-int}
-PUBLIC_BRIDGE=${PUBLIC_BRIDGE:-br-ex}
 OVS_DATAPATH_TYPE=${OVS_DATAPATH_TYPE:-""}
 
 function is_neutron_ovs_base_plugin {