Shared Buffer Approach in Fault Tolerant Networks

Abstract

In this study, we showed that switches that incorporate shared buffer switching elements (SE) provide high buffer utilization and needs least amount of buffer space. One of the main factors that affect the buffering strategy is the buffer management approach. In order to manage the incoming packets in each buffered switching element, two buffer handling techniques are proposed: the first-in-first-out (FIFO) configuration which employs backpressure control flow mechanism and follows the FIFO policy in handling the buffer; and the look-ahead configuration which still follows all the features of the FIFO scheme but uses the buffer only when needed. Tagle-Sharma network is used as a model network. Simulation results show that both schemes give high throughput under uniform random traffic. Introduction of the deadline keeps the delay performance of the network low. One drawback of the look-ahead strategy is that when the packet bypasses the buffer of the current SE, back pressure mechanism is not applied and the packet reaches its destination faster, thus could cause an overflow of buffer in the next stage of the network. The look-ahead scheme offers better transmission delay performance than the FIFO approach.