diff --git a/README.md b/README.md
index a1fe8f9d..42260923 100644
--- a/README.md
+++ b/README.md
@@ -178,3 +178,65 @@ By default, the charm will configure Open vSwitch/DPDK to consume a processor co
 **NOTE:** Enabling DPDK support automatically disables security groups for instances.
 
 [dpdk-nics]: http://dpdk.org/doc/nics
+
+# Port Configuration
+
+**NOTE:** External port configuration only applies when DVR mode is enabled.
+
+All network types (internal, external) are configured with bridge-mappings and
+data-port and the flat-network-providers configuration option of the
+neutron-api charm.  Once deployed, you can configure the network specifics
+using neutron net-create.
+
+If the device name is not consistent between hosts, you can specify the same
+bridge multiple times with MAC addresses instead of interface names.  The charm
+will loop through the list and configure the first matching interface.
+
+Basic configuration of a single external network, typically used as floating IP
+addresses combined with a GRE private network:
+
+    neutron-openvswitch:
+        bridge-mappings:         physnet1:br-ex
+        data-port:               br-ex:eth1
+    neutron-api:
+        flat-network-providers:  physnet1
+
+    neutron net-create --provider:network_type flat \
+        --provider:physical_network physnet1 --router:external=true \
+        external
+    neutron router-gateway-set provider external
+
+Alternative configuration with two networks, where the internal private
+network is directly connected to the gateway with public IP addresses but a
+floating IP address range is also offered.
+
+    neutron-openvswitch:
+        bridge-mappings:         physnet1:br-data external:br-ex
+        data-port:               br-data:eth1 br-ex:eth2
+    neutron-api:
+        flat-network-providers:  physnet1 external
+
+Alternative configuration with two external networks, one for public instance
+addresses and one for floating IP addresses.  Both networks are on the same
+physical network connection (but they might be on different VLANs, that is
+configured later using neutron net-create).
+
+    neutron-openvswitch:
+        bridge-mappings:         physnet1:br-data
+        data-port:               br-data:eth1
+    neutron-api:
+        flat-network-providers:  physnet1
+
+    neutron net-create --provider:network_type vlan \
+        --provider:segmentation_id 400 \
+        --provider:physical_network physnet1 --shared external
+    neutron net-create --provider:network_type vlan \
+        --provider:segmentation_id 401 \
+        --provider:physical_network physnet1 --shared --router:external=true \
+        floating
+    neutron router-gateway-set provider floating
+
+This replaces the previous system of using ext-port, which always created a bridge
+called br-ex for external networks which was used implicitly by external router
+interfaces.
+
diff --git a/config.yaml b/config.yaml
index 5fb506c0..d8e1e62f 100644
--- a/config.yaml
+++ b/config.yaml
@@ -99,6 +99,10 @@ options:
     type: string
     default:
     description: |
+      Deprecated: Use bridge-mappings and data-port to create a network
+      which can be used for external connectivity.  You can call the network
+      external and the bridge br-ex by convention, but neither is required
+
       A space-separated list of external ports to use for routing of instance
       traffic to the external public network. Valid values are either MAC
       addresses (in which case only MAC addresses for interfaces without an IP
diff --git a/hooks/neutron_ovs_context.py b/hooks/neutron_ovs_context.py
index c807d751..f90dcc68 100644
--- a/hooks/neutron_ovs_context.py
+++ b/hooks/neutron_ovs_context.py
@@ -107,8 +107,11 @@ class L3AgentContext(OSContextGenerator):
         ctxt = {}
         if neutron_api_settings['enable_dvr']:
             ctxt['agent_mode'] = 'dvr'
+            if not config('ext-port'):
+                ctxt['external_configuration_new'] = True
         else:
             ctxt['agent_mode'] = 'legacy'
+
         return ctxt
 
 
diff --git a/templates/juno/l3_agent.ini b/templates/juno/l3_agent.ini
index 8e93c71a..9dac0696 100644
--- a/templates/juno/l3_agent.ini
+++ b/templates/juno/l3_agent.ini
@@ -5,3 +5,7 @@
 [DEFAULT]
 interface_driver = neutron.agent.linux.interface.OVSInterfaceDriver
 agent_mode = {{ agent_mode }}
+{% if external_configuration_new -%}
+gateway_external_network_id =
+external_network_bridge =
+{% endif %}
diff --git a/unit_tests/test_neutron_ovs_context.py b/unit_tests/test_neutron_ovs_context.py
index 5cead5ea..d64da9f0 100644
--- a/unit_tests/test_neutron_ovs_context.py
+++ b/unit_tests/test_neutron_ovs_context.py
@@ -244,7 +244,10 @@ class L3AgentContextTest(CharmTestCase):
             'network-device-mtu': 1500,
         }
         _rget.side_effect = lambda *args, **kwargs: rdata
-        self.assertEquals(context.L3AgentContext()(), {'agent_mode': 'dvr'})
+        self.assertEquals(
+            context.L3AgentContext()(), {'agent_mode': 'dvr',
+                                         'external_configuration_new': True}
+        )
 
     @patch.object(charmhelpers.contrib.openstack.context, 'relation_get')
     @patch.object(charmhelpers.contrib.openstack.context, 'relation_ids')