def METHOD_NAME(tgen):
    for routern in range(1, 4):
        tgen.add_router("r{}".format(routern))
    # On main router
    # First switch is for a dummy interface (for local network)
    switch = tgen.add_switch("sw1")
    switch.add_link(tgen.gears["r1"])
    # Switches for zebra
    # switch 2 switch is for connection to zebra router
    switch = tgen.add_switch("sw2")
    switch.add_link(tgen.gears["r1"])
    switch.add_link(tgen.gears["r2"])
    # switch 4 is stub on remote zebra router
    switch = tgen.add_switch("sw4")
    switch.add_link(tgen.gears["r3"])
    # switch 3 is between zebra routers
    switch = tgen.add_switch("sw3")
    switch.add_link(tgen.gears["r2"])
    switch.add_link(tgen.gears["r3"])