diff --git a/neutron/templates/bin/_neutron-openvswitch-agent.sh.tpl b/neutron/templates/bin/_neutron-openvswitch-agent.sh.tpl
index 7b51ce5f44..6f3310577f 100644
--- a/neutron/templates/bin/_neutron-openvswitch-agent.sh.tpl
+++ b/neutron/templates/bin/_neutron-openvswitch-agent.sh.tpl
@@ -26,9 +26,14 @@ chown neutron: /run/openvswitch/db.sock
 # see https://github.com/att-comdev/openstack-helm/issues/88
 timeout 3m neutron-sanity-check --config-file /etc/neutron/neutron.conf --config-file /etc/neutron/plugins/ml2/openvswitch_agent.ini --ovsdb_native --nokeepalived_ipv6_support
 
+tunnel_interface={{ .Values.network.interface.tunnel }}
+if [ not $tunnel_interface ] ; then
+    # search for interface with default routing
+    tunnel_interface=$(ip r | grep default | grep -oP '(?<=dev ).*')
+fi
 
 # determine local-ip dynamically based on interface provided but only if tunnel_types is not null
-IP=$(ip a s {{ .Values.network.interface.tunnel | default .Values.network.interface.default}} | grep 'inet ' | awk '{print $2}' | awk -F "/" '{print $1}')
+IP=$(ip a s $tunnel_interface | grep 'inet ' | awk '{print $2}' | awk -F "/" '{print $1}')
 cat <<EOF>/tmp/ml2-local-ip.ini
 [ovs]
 local_ip = $IP
diff --git a/neutron/templates/bin/_openvswitch-ensure-configured.sh.tpl b/neutron/templates/bin/_openvswitch-ensure-configured.sh.tpl
index 48671c4ba1..7eb703724c 100644
--- a/neutron/templates/bin/_openvswitch-ensure-configured.sh.tpl
+++ b/neutron/templates/bin/_openvswitch-ensure-configured.sh.tpl
@@ -14,6 +14,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+{{- if not .Values.ml2 -}}{{- set . "Values.ml2" dict -}}{{- end -}}
+{{- if not .Values.ml2.ovs -}}{{- set . "Values.ml2.ovs" dict -}}{{- end -}}
+{{- if not .Values.ml2.ovs.auto_bridge_add -}}{{- set . "Values.ml2.ovs.auto_bridge_add" dict -}}{{- end -}}
+
 set -x
 
 bridge=$1
@@ -23,12 +27,16 @@ port=$2
 # and br-int and br-tun are assumed and handled
 # by the agent
 ovs-vsctl --no-wait --may-exist add-br $bridge
-ovs-vsctl --no-wait --may-exist add-port $bridge $port
-ip link set dev $port up
+if [ $port] ; then
+  ovs-vsctl --no-wait --may-exist add-port $bridge $port
+  ip link set dev $port up
+fi
 
 # handle any bridge mappings
 {{- range $bridge, $port := .Values.ml2.ovs.auto_bridge_add }}
 ovs-vsctl --no-wait --may-exist add-br {{ $bridge }}
-ovs-vsctl --no-wait --may-exist add-port {{ $bridge }} {{ $port }}
-ip link set dev {{ $port }} up
+if [ {{  $port }} ] ; then
+    ovs-vsctl --no-wait --may-exist add-port {{ $bridge }} {{ $port }}
+    ip link set dev {{ $port }} up
+fi
 {{- end}}
diff --git a/neutron/templates/bin/_openvswitch-vswitchd.sh.tpl b/neutron/templates/bin/_openvswitch-vswitchd.sh.tpl
index c93168ae08..1e0c0d1db0 100644
--- a/neutron/templates/bin/_openvswitch-vswitchd.sh.tpl
+++ b/neutron/templates/bin/_openvswitch-vswitchd.sh.tpl
@@ -23,5 +23,5 @@ modprobe gre
 modprobe vxlan
 
 ovs-vsctl --no-wait show
-bash /tmp/openvswitch-ensure-configured.sh {{ .Values.network.external_bridge }} {{ .Values.network.interface.external | default .Values.network.interface.default }}
+bash /tmp/openvswitch-ensure-configured.sh {{ .Values.network.external_bridge }} {{ .Values.network.interface.external }}
 exec /usr/sbin/ovs-vswitchd unix:/run/openvswitch/db.sock --mlockall -vconsole:emer -vconsole:err -vconsole:info
diff --git a/neutron/values.yaml b/neutron/values.yaml
index c518e27591..19def0c7da 100644
--- a/neutron/values.yaml
+++ b/neutron/values.yaml
@@ -76,8 +76,11 @@ network:
   external_bridge: br-ex
   ip_address: 0.0.0.0
   interface:
-    external: enp12s0f0
-    default: enp11s0f0
+  # External interface will be automatically added to external_bridge. Default is null.
+  # Tunnel interface will be used for VXLAN tunneling. Default is null, with
+  # fallback mechanism to search for interface with default routing.
+    external: null
+    tunnel: null
   server:
     name: "neutron-server"
     port: 9696
@@ -112,12 +115,14 @@ metadata_agent:
 metadata:
   workers: 4
 
+
 ml2:
   ovs:
-    auto_bridge_add:
-      br-physnet1: enp11s0f0
-    bridge_mappings:
-      - "physnet1:br-physnet1"
+    auto_bridge_add: []
+# To automatically add a physical interface to a specific bridge using,
+# for example eth3 to bridge br-physnet1 define the following key/value
+# in auto_bridge_add:
+#       - br-physnet1:eth3
 
 dependencies:
   db_init:
@@ -341,10 +346,13 @@ conf:
       neutron:
         ml2:
           flat_networks: "*"
-    ml2_type_vlan:
-      neutron:
-        ml2:
-          network_vlan_ranges: "physnet1:1100:1110"
+    # If you want to use the external network as a tagged provider network,
+    # a range should be specified including the intended VLAN target
+    # using ml2_type_vlan.neutron.ml2.network_vlan_ranges:
+    # ml2_type_vlan:
+    #   neutron:
+    #     ml2:
+    #       network_vlan_ranges: "external:1100:1110"
   ml2_conf_sriov:
     override:
     append:
@@ -377,12 +385,18 @@ conf:
   openvswitch_agent:
     override:
     append:
-    ovs:
+    agent:
       neutron:
         ml2:
           ovs:
             agent:
               tunnel_types: vxlan
+    ovs:
+      neutron:
+        ml2:
+          ovs:
+            agent:
+              bridge_mappings: "external:br-ex"
               ovsdb_connection: unix:/var/run/openvswitch/db.sock
     securitygroup:
       neutron: