'Function that returns the router to fip interface name and ip.'

def get_rtr_fip_ip_and_interface_name(self):

    if (self.rtr_fip_subnet is None):
        self.rtr_fip_subnet = self.fip_ns.local_subnets.allocate(self.router_id)
    (rtr_2_fip, __) = self.rtr_fip_subnet.get_pair()
    fip_2_rtr_name = self.fip_ns.get_int_device_name(self.router_id)
    return (rtr_2_fip.ip, fip_2_rtr_name)
