CONTINUOUS ROUTING IN PACKET SWITCHES

Abstract

Considering continuous routing, we analyze the transient behavior of n×n routers with input buffering, split input buffering, output buffering, and central buffering with dedicated virtual circuits, one for each source-destination pair in a network. Assuming similar buffer space requirements, output buffering has the highest throughput. Split input buffering and central buffering have comparable performance; split input buffering slightly outperforms central buffering for large switches. Input buffering is known to saturate at packet generating rates above 0.586. By extending these models, two 1024-node, unique-path multistage networks configured with (approximately-modeled) input buffered STC104 32×32 switches, or central buffered Telegraphos 4×4 switches (Telegraphos I version) are compared. Surprisingly, the network configured with smaller switches performs better. This is due to the higher peak bandwidth of the Telegraphos switch and saturation of the input buffered STC104 switch.