First stage multicasting in a growable packet (ATM) switch

A three-stage packet switch architecture that uses a two stage, self-routing, memoryless, interconnection network to interconnect a third stage of smaller packet switches was proposed by K.Y. Eng. et al. (Proc. IEEE Globecom, p.1159-65, vol.2, 1989). Two new routing algorithms that facilitate the multicastings of packets with this architecture are proposed. The two routing algorithms, one of which duplicates packets at only the first stage and the other which duplicates packets at the first and third stages, require only minimal alterations to the switch. An analysis is made of the switch´s multicast performance, finding an overbound on the packet loss probability. The analysis, which identifies three sources of packet loss, shows that good multicast performance is maintained with only a small increase in the architecture´s expansion provided that, on average, the load is not severely concentrated onto any particular input section as a result of multicasting