Threshold-based Partial Sharing Buffer Management in a Shared Buffer Packet Switch

In a shared buffer packet switch, a good buffer management scheme will reduce the overall packet loss probability and improve the fairness among different output queues. In this paper, a novel buffer control scheme called threshold-based partial sharing (TPS) is proposed. The key idea of the TPS is to separate the output ports into active and inactive output ports according to whether their queue lengths are larger than the fair buffer allocation factor or not. When the remained buffer size is larger than a certain threshold value, all arrival packets are accepted. Otherwise, only the packets destined for inactive output ports are admitted to enter the shard buffer. The TPS scheme possesses the dynamic adjustability of pushout (PO) without the implementation complexity. Instead, the TPS uses a simple static threshold for control. Computer simulations are used to compare the loss performance of TPS, dynamic threshold (DT), and PO. TPS control is shown to be more robust to variation in traffic conditions than DT control and close to the loss performance of PO that is considered as optimal in terms of fairness and overall packet loss probability. key words: threshold, partial sharing, fairness, robust