Flit-serial packet routing on meshes and tori

Abstract

In this paper we consider theflit-serial packet-routing problem, where each packet consists of a sequence ofk flits and is, thus, called asnake. Based on the properties of the snake during the routing, we give a formal definition of three different packet-routing models, namely, thestore-and-forward model, thecut-through model, and thecut-through with partial cuts model. Surprisingly, all previous work has focused on the store-and-forward model. We also introduce therestricted cut-through model, which is unrealistic, but is proved to be a very powerful tool in the effort to bound the time required by a routing problem. We study the cut-through with partial cuts model which is most commonly used in practice. We present the first algorithms, deterministic and probabilistic, based on this model for the permutation routing problem on a chain, on a square mesh, and on a square torus.