Traffic studies of unbuffered Delta networks

This paper considers performance issues associated with a class of interconnection networks called hierarchical interconnection networks. It focuses specifically on an unbuffered Delta network. The performance of such networks under a nonuniform (hot-spot) traffic pattern is analyzed. Particular attention is given to characterizing the overflow traffic of unsuccessfully transmitted packets. It is shown that the overflow traffic from a packet-switched Delta network is (fractionally) hotter than the offered load. Using simulation techniques, this result is extended to a more realistic circuit-switched network in discrete time with nonnegligible set-up times and limited retrials.