A multicast broadband switching module in a hybrid ATM environment

On the basis of the assumption of a hybrid asynchronous transfer mode (ATM) environment in which two classes of traffic are defined, an architecture for a broadband switching module is proposed. The described architecture provides both unicast and multicast connections for two kinds of information flows and guarantees a constant switching delay for high-priority communications. This goal is achieved by exploiting the nonblocking features of the switching fabric, which consists of buffered delta networks assembled to make up a parallel delta network. In the module, the high-priority multicast connections are performed in two steps: in the first one the copy process takes place, and a multicast routing algorithm is proposed; in the second, the copies are addressed toward the requested output ports as a set of unicast paths. The two phases are accomplished onto the same switching fabric, achieving a full pipelining of the information flows