A method of making network services available to a subscriber of a first mobile communications network when the subscriber roams in a second mobile communications network. The carrier is configured with an electrically nonconductive smooth curved surface at a distal end of the bore. The method also includes forming the IP traceback path as packets are received by a destination system and completing the traceback path after a determined number of packets are received by the destination system. The cluster management unit of the one server carries out a corresponding state-transition based on this determination result and state transition diagram. The anchoring of the bands at ground or below ground locations on both sides of the barrier provides stopping power without requiring massive barrier structures to be raised and lowered in use.