Combined Input-Crosspoint Buffered Packet Switch with Shared Crosspoint Buffers1

The amount of memory in buffered crossbars in combined input-crosspoint buffered switches is proportional to the number of crosspoints, or O(N), where N is the number of ports, and to the crosspoint buffer size, which is defined by the distance between the line cards and the buffered crossbar, to achieve 100% throughput under high-speed data flows. A long distance between these two components can make a buffered crossbar costly to implement. In this paper, we propose a combined inputshared-crosspoint buffered packet switch that uses small crosspoint buffers to support long round-trip times, which consider the distance between the line card and the buffered crossbar. The proposed switch reduces the required buffer memory of the buffered crossbar by 50% or more, and uses no speedup.