Abstract

An important aspect in the design of a 2-D parallel processor is efficient interconnections. Crossbar networks(CBN) are considered to be the most desirable candidates because every processor can communicate with every other processor without conflicts. Implementing a large 2-D CBN, however, is very difficult[1]. A Clos network(CN)[2], Clos(p,q,r), as shown in Fig. 1 is proposed to replace the CBN. In Fig. 1, each block represents a feasible subcrossbar of medium size. The CN has the same characteristics as the CBN. The CN is a nonblocking network with which it is always possible to connect together an idle input-output pair of processors without disturbing existing connections, if q≥2p-1 is satisfied. Both one-to-one and one-to-many connections are available in the CN. The most important factor is that the number of switching elements has been reduced in the CN(~10:1 for a 1000x1000 network, as compared with the CBN). The difficulty of determining connections, however, is a major problem to be overcome[3,4].

© 1987 Optical Society of America