Abstract: When a first MS control signalling device that controls a mobile station fails, a second MS control signalling device takes over the processing of the first MS control signalling device. The second MS control signalling device requests a RLC parameter necessary for communication of the mobile station, and the mobile station transmits the requested RLC parameter to the second MS control signalling device. The second MS control signalling device controls communication of the mobile station, using the obtained RLC parameter. A data path for transmitting user data of the mobile station is not released but is held when the MS control signalling devices are switched.

Abstract: A communication system includes a first controller which includes a first retransmission request unit to request a mobile station, as a source of a first service connection request, to retransmit the first service connection request addressed to a second controller, which is able to set a communication line with a rate that is higher than the rate of the first controller, when receiving the first service connection request requesting a connection related to a first service from the mobile station, and a second controller which includes a second retransmission request unit to request the mobile station, as the source of a second service connection request, to retransmit the second service connection request addressed to the first controller, which is able to set a communication line, when receiving the second service connection request requesting a connection related to the second service from the mobile station.

Abstract: When a first MS control signalling device that controls a mobile station fails, a second MS control signalling device takes over the processing of the first MS control signalling device. The second MS control signalling device requests a RLC parameter necessary for communication of the mobile station, and the mobile station transmits the requested RLC parameter to the second MS control signalling device. The second MS control signalling device controls communication of the mobile station, using the obtained RLC parameter. A data path for transmitting user data of the mobile station is not released but is held when the MS control signalling devices are switched.

Abstract: An ATM switch comprises a detector that detects impairments in signal lines, and a controller that controls the preservation of paths that have been established by call control via a signal line when an impairment has been detected on a signal line by the detector. When an impairment has occurred only on a signal line, interruptions in communications services are prevented by causing the data line paths to be preserved rather than released.

Abstract: An switching system for routing a call setup request received from a subscriber device to a desired network among multiple networks having two or more different routing methods, based on information included in the call setup request.