H-Bus: an experimental ATM-based optical premises network

An optical customer premises network (CPN), called H-Bus, designed to interface future broadband ISDN signals and distribute available bandwidth to terminal equipment connected to the CPN, is discussed. Key features of this network are the use of optical fiber as a transmission medium and a hybrid architecture, namely, a broadcast bus for the downstream (network interface to subscriber terminal) and a looped bus for the upstream (subscriber terminal to network interface) traffic. The physical layer of the network makes use of the synchronous optical network (SONET) transmission format. The user information is carried using the asynchronous transfer mode (ATM) technique. The reliability of H-Bus is improved through the use of a network component called an optical protection socket (OPS). This is an automatic optical bypass switch that protects the CPN in the case of individual node failures. To resolve any access contention on the upstream bus, a multipriority media access control protocol has been defined. Its performance is compared with that of protocols used in other high-speed local area networks