Multicast contention resolution with single-cycle windowing using content addressable FIFO's

Asynchronous transfer mode (ATM) has been designated as the switching environment for future broadband integrated services digital networks (BISDN) networks and services. Although input-buffered space switches are more economical and simpler to implement than output-buffered space switches, they suffer from external blocking because of destination port contention. We review contention resolution methods used to avoid external blocking, and choose a solution based on ring reservation, resulting in an elegant and efficient mechanism requiring only nearest-neighbor communications. In addition to external blocking, space switches suffer from head-of-line (HOL) blocking, and our technique alleviates HOL blocking without arbitration time overhead. This method makes use of a novel content addressable first in/first out (CAFIFO) to achieve single-cycle windowing, and the CAFIFO design and operation are described in detail. High multicast throughput is achieved by employing call-splitting. Multiple latency priorities can also be supported. Simulation results, for both unicast and multicast switching, and both random and bursty traffic, highlight the versatility and excellent performance of the CAFIFO-based switch.