A broadband switching system for public network

Research and development of broadband switching systems for public networks is described. For early introduction of broadband ISDN in the public network, all of the necessary network elements, eg. terminal equipment, subscriber loop equipment; switching system, etc are being developed. From the viewpoint of services, broadband is necessary for interactive image application. Broadband network services can be mapped into call switching, distribution, virtual network and private line. For subscriber loop network double star configuration, distribution loop and feeder loop is adopted. The UNI is 622Mb/s including combination of ATM channels and STM channels. The switching system is composed of the Host Switch and Broadband Remote Switching Unit (BRSU), to provide both ATM and STM switching. CATV service is provided by an STM distribution switch in the BRSU. Signaling protocol for UNI is based on DSSI for N-ISDN. The signaling between BRSU and the Host is based on ISUP of CCS7. Customer premises network is based on DQDB or passive bus method. The protoope system developed in 1989 provided video telephony, CATV, CBR and N-ISDN services.