Universal routing in distributed networks

We show that universal routing can be achieved with low overhead in distributed networks. The validity of our results rests on a new network called the fat-stack. We show that from a routing perspective the fat-stack is efficient and is suitable for use as a baseline distributed network. We prove that the fat-stack is universal by routing efficiency. A requirement for the fat-stack to be universal is that link capacities double up the levels of the network. We use methods developed in the areas of VLSI and processor interconnect for much of our analysis. Our universality proof shows that a fat-stack of area θ(A) can simulate any competing network of area A with O(log^3/2 A) overhead independently of wire delay. The universality result implies that the fat-stack of a given size is nearly the best routing network of that size. The fat-stack is also the minimal universal network for an O(log^3/2 A) overhead in terms of number of links.