Hot Potato Worm Routing via Store-and-Forward Packet Routing

The theory of worm routing (rather than packet routing) has recently attracted increased attention as an abstraction of the underlying communication mechanisms in many parallel machines. Routing the worms in the hot potato style is a desired form of communication in high-speed optical interconnection networks. In this work, we develop a simple method for the design of parallel hot potato worm routing algorithms. Our basic approach is to simulate known packet routing algorithms, so that in each step worms are moved around instead of packets. By plugging in known results for packet routing, we get the fastest (so far) deterministic batch worm routing algorithms. Although the results are given for permutation routing on the mesh and the hypercube, the general method can be applied to many other networks and to more general communication patterns as well. Moreover, once better routing algorithms are found for the underlying network, the worm routing algorithms improve as well.