Performance analysis of threshold-based selective drop mechanism for high performance packet switches

In this paper, a simple and efficient threshold-based selective drop (TSD) buffer management scheme is proposed to improve the overall loss performance and fairness by regulating the buffer sharing in a packet switch. The key idea of TSD is to divide the output ports into active or inactive output ports by comparing their queue lengths with a fair share buffer size. When total queue length equals or exceeds the threshold value, only arrival packets destined to inactive output ports are admitted to enter the shared buffer. A transient analysis of TSD is derived to prove the fairness of buffer allocation among different output queues. We use computer simulation to compare the overall loss performance of TSD, complete sharing (CS), complete partitioning (CP), dynamic threshold (DT) and pushout (PO). The TSD method is shown to be more robust than CS, CP and DT methods under different traffic conditions.