Comment 11 for bug 1374473

I used this link as a guide: http://blog.oddbit.com/2014/05/28/multiple-external-networks-wit/

For one thing, I created a second external bridge for the second external network. The ml2_conf.ini file then has a config to map the physical interfaces to the bridges ('bridge_mappings').

Also, the l3_agent.ini needs to have the 'external_network_bridge' and 'gateway_external_network_id' must be set to blank. Otherwise the agent tries to retrieve the network id from the plugin.

Have you tried doing multiple external networks using the 'default' config for a centralized router? I got different errors when I tried it.