An improvement mechanism for low priority traffic TCP performance in Strict Priority Queueing
Mahdi Rahimi, Vahab Pournaghshband · 2016
Strict Priority Queuing (SPQ) is a widely used queuing method for applying preferential service on edge networks. SPQ, in presence of persistent high priority traffic, is known to behave in a very hostile manner toward low priority flows, causing them to experience poor TCP performance. This often leads to substantial packet losses, which consequently results in aggressive reduction in the congestion window size at the sender. This severe performance degradation then leads to channel underutilization when the high priority queue is emptied. In this paper, we introduce Amicable Strict Priority Queuing, an approach to improve the TCP performance of low priority traffic, in the presence of interruptions caused by a surge of high priority traffic flows. Our proposed approach has two major advantages. First, it does not require any changes to the TCP stack of the end hosts. Second, through the simple augmentation introduced in this paper, no modification to the existing SPQ-enabled switches and routers is required, making it readily deployable in current systems. Experiments in a simulated environment confirm the validity of our proposed approach.