A router architecture for flexible routing and switching in multihop point-to-point networks

Modern parallel and distributed applications have a wide range of communica tion characteristics and performance requirements. These diverse characteri stics affect the performance and suitability of particular routing and swit ching policies in multihop point-to-point networks. In this paper, we ident ify a core set of architectural features necessary for flexible selection a nd implementation of multiple routing and switching schemes. Using this, we present a flexible router whose routing and switching policies can be tail ored to the application, allowing the network to meet these diverse needs. By dedicating a small programmable processor to each incoming link, we can implement wormhole, Virtual cut-through, and packet switching. as well as h ybrid switching schemes, each under a variety of unicast and multicast rout ing algorithms. In addition, a flexible router can support several applicat ions or traffic types simultaneously, enabling better support of applicatio ns with multiple traffic classes. We have designed, implemented, and fabric ated the Programmable Pouting Controller(PRC). Cycle-level simulations of m esh-connected PRCs also demonstrate that flexible routing and switching can significantly enhance application performance.