We present new results derived from the packet loss analysis of ageneric Nx/N nonblocking ATM switches with speedup factor m and finiteinput/output buffers under nonuniform traffic. We adopt a queue lossscheme which allows packet loss at output buffers if the finite outputbuffers at each output port cannot accommodate all arriving packets.Exact packet loss probabilities of the switch at inputs and outputs arederived by using the matrix geometric solution technique. Our discretetime Markov chain analysis is more accurate than continuous timeanalysis, considering file fixed ATM cell size. It is shown that theoptimal packet loss performance is obtained at the speed-up factor 2,not at larger values, with moderate input and output buffer sizes lessthan 30, for the practical range of uniform traffic load up to 0.8, tomeet the given packet loss requirement, say 10-9. This resultsuggests that we do not need to design with large speed-up factor forthe practical range of packet loss and track load requirements, knowingthat the large speed-up factor often means excessive cost and complexityinvolved in implementing the switch design. We also study how thedifferent sizes of input and output buffers affect the switchperformance. In particular, for nonuniform traffic study, we investigatethe effect of each nonuniform parameters, such as nonuniformity at theinput/output and output port addressing, on the switch performance.Finally, we introduce a concept of output traffic pressure, which isdefined as output traffic intensity felt at unit buffer. Based on thisidea, we propose an output buffer sharing scheme, to improve the packetloss performance degraded by nonuniform traffic. With this scheme we cansignificantly improve packet loss performance of nonuniform traffic.Furthermore, with a small increase in buffer budget we may achieve theperformance very close to that of uniform traffic
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