Contention‐tolerant crossbar packet switches
Guannan Qu, Hyung Jae Chang, Jianping Wang, Zhiyi Fang, S. Q. Zheng · International Journal of Communication Systems · 2010
Abstract We propose an innovative agile crossbar switch architecture called contention‐tolerant crossbar, denoted by CTC(N). Unlike the conventional crossbar and the crossbar with crosspoint buffers, which require complex hardware resolvers to grant one out of multiple output requests, CTC(N) can tolerate output contentions by a pipelining mechanism, with pipeline stages implemented as buffers in input ports. These buffers are used to decouple the scheduling task intoNindependent parts in such a way thatNschedulers are located inNinput ports, and they operate independently and in parallel. Without using arbiters and/or crosspoint buffers that require additional chip area, the CTC(N) switch is more scalable than existing crossbars. We analyze the throughput of CTC(N) switch, and find 63% throughput bottleneck. For achieving 100%, we consider two approaches: using internal speedup and using space multiplexing without internal speedup. We prove that 100% throughput can be achieved with internal speedup 2 or using two layers of CTC(N) fabric mathematically. Our simulation results validate our theoretical analysis. Copyright © 2010 John Wiley & Sons, Ltd.