'Get one external network id for l3 agent.
l3 agent expects only one external network when it performs
this query.'

def get_external_network_id(self, context, **kwargs):

    context = neutron_context.get_admin_context()
    net_id = self.plugin.get_external_network_id(context)
    LOG.debug('External    network    ID    returned    to    l3    agent:    %s', net_id)
    return net_id
