Comment 1 for bug 1544706

This is mostly like DVR in ML2/ovs - each compute node has a direct connection to the external network; east-west l3 traffic is optimized, north-south happens directly on the compute nodes.

Quick impact analysis (with T-Shirt sizing in (SML)):

odl-controller:

   add configuration option for enabling l3 forwarding mode (S)

neutron-api-odl/neutron-api:

   support specification of service plugins so that we can switch out the default router option with odl-router (M)

openvswitch-odl:

   add support for ext-port configuration, creation of br-data bridge etc... (S)

neutron-gateway:

   add new profile ovs-odl-l3 which disables the l3 and associated daemons (lbaas, vpnaas, metering) on the gateway; just dhcp and metadata (S)