Incremental design of scalable interconnection networks using basic building blocks

We present an incremental design of scalable interconnection networks using basic building blocks, including both network topologies and routing. We consider wormhole-routed small-scale 2D meshes as basic building blocks. The minimum requirement to expand these networks is a single building block. This implies that the network does not have to maintain the regular 2D mesh topology. We introduce some new topologies: incomplete meshes based on those adaptive routing algorithms designed from the turn model and extended incomplete meshes based on XY routing. We show that the original routing function can be adopted to send a message between any source and destination without using store-and-forward and causing deadlock. The way we construct the network incrementally minimizes the amount of rewiring and keeps high bisection density and short diameter of the network. The design methods can be used to economically and incrementally build expandable and scalable parallel computers.