Seen with the latest ovsdb/odl-neutron master code.

Setup:
1. OpenStack configured using Devstack with ODL as external controller.
2. Using ODL_L3 inst ead of neutron l3-agent.
3. Configured ODL_PROVIDER_MAPPINGS="physnet1:eth1" and PUBLIC_INTERFACE="eth1" in local.conf
4. service_plugins =   is properly configured in neutron.conf
5. In ODL etc/custom.properties file, enabled ovsdb.l3.fwd.enabled=yes
6. On ODL side, started the controller and installed the feature odl-ovsdb-openstack.
7. ./stack.sh is successful.

Now in this setup, when I create a neutron router and associate a tenant subnet to the neutron router, I'm seeing the error "Service Unavailable"
a. neutron router-create r1
b. neutron net-create t1
c. neutron subnet-create --name ts1 t1 10.0.0.0/24
d. neutron router-interface-add r1 ts1

Step d above returns the error and karaf logs show an exception http://paste.openstack.org/show/486263/

Output of ovs-vsctl show on the node - http://paste.openstack.org/show/486262/

Network topology when queried from ODL, displays: http://paste.openstack.org/show/486264/

PS: In the same setup, when I use ODL Lithium SR3 (instead of ODL OVSDB Master) it works fine.