Adaptive deadlock-free worm-hole routing in hypercubes

Abstract

Two new algorithms for worm-hole routing in the hypercube are presented. The first hypercube algorithm is adaptive, but non-minimal in the sense that some derouting is permitted. Then another deadlock-free adaptive worm-hole based routing algorithm for the hypercube interconnection is presented which is minimal. Finally some well-known worm-hole algorithms for the hypercube were evaluated together with the new ones on a hypercube of 2/sup 10/ nodes. One oblivious algorithm, the Dimension-Order, or E-Cube routing algorithm (W. Dally, C. Seitz, 1987) was tried. In addition, three partially adaptive algorithms were considered: the Hanging algorithm (Y. Birk, P. Gibbons, D. Soroker, J. Sanz, 1989 and S. Konstantinidou, 1990), the Zenith algorithm (S. Konstantinidou, 1990), and the Hanging-Order algorithm (G.-M. Chia, S. Chalasani, C.S. Raghavendra, 1991). Finally, a fully adaptive minimal algorithm presented independently by L. Gravano, G. Pifarre, S.A. Felperin and J. Sanz (1991) and J. Duato was tried. This algorithm allows each message to choose adaptively among all the shortest paths from its source to its destination. Only four virtual channels per physical link are needed to achieve this. This technique is referred to as Fully. The results obtained show that the two new algorithms are good candidates as a choice for worm-hole routing in the hypercube network.<>