An evaluation of planar-adaptive routing (PAR)

Network performance can be improved by allowing adaptive routing, but doing so introduces new possibilities of deadlock which can overwhelm the flexibility advantages. Planar-adaptive routing resolves this tension by limiting adaptive routing to a series of two-dimensional planes, reducing hardware requirements for deadlock prevention. The authors explore the performance of planar-adaptive routers for two, three, and four-dimensional networks. Under nonuniform traffic loads, the planar-adaptive router significantly outperforms the dimension-order router, while giving comparable performance under uniform loads. With equal resources, the planar-adaptive router provides performance superior to fully adaptive routers because it requires less resources for deadlock prevention, freeing resources to increase the number of virtual lanes.>