def METHOD_NAME(mod):
    tgen = Topogen(build_topo, mod.__name__)
    tgen.start_topology()
    router_list = tgen.routers()
    for routern in range(1, 4):
        tgen.gears["r{}".format(routern)].cmd("ip link add vrf1 type vrf table 10")
        tgen.gears["r{}".format(routern)].cmd("ip link set vrf1 up")
        tgen.gears["r{}".format(routern)].cmd("ip address add dev vrf1 {}.{}.{}.{}/32".format(routern, routern, routern,routern))
    tgen.gears["r2"].cmd("ip address add dev vrf1 192.0.2.8/32")
    tgen.gears["r3"].cmd("ip address add dev vrf1 192.0.2.8/32")
    for i, (rname, router) in enumerate(router_list.items(), 1):
        router.load_config(
            TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
        )
        router.load_config(
            TopoRouter.RD_BGP, os.path.join(CWD, "{}/bgpd.conf".format(rname))
        )
        router.load_config(
            TopoRouter.RD_LDP, os.path.join(CWD, "{}/ldpd.conf".format(rname))
        )
    tgen.start_router()
    tgen.gears["r1"].cmd("ip route add 192.0.2.2 via 192.168.1.2 metric 20")
    tgen.gears["r1"].cmd("ip route add 192.0.2.3 via 192.168.2.2 metric 20")