Implementation of PI² queuing discipline for classic TCP traffic in ns-3

Abstract

This paper presents the implementation and validation of PI 2 Active Queue Management (AQM) algorithm in ns-3. PI 2 provides an alternate design and implementation to Proportional Integral controller Enhanced (PIE) algorithm without affecting the performance benefits it provides in tackling the problem of bufferbloat. Bufferbloat is a situation arising due to the presence of large unmanaged buffers in the network. It results in increased latency and therefore, degrades the performance of delay-sensitive traffic. PIE algorithm tries to minimize the queuing delay by auto-tuning its control parameters. However, with PI 2 , this auto-tuning can be replaced by just squaring the packet drop probability. In this paper, we implement a model for PI 2 in ns-3 and verify its correctness by comparing the results obtained from it to those obtained from the PIE model in ns-3. The results indicate that PI 2 offers a simple design and achieves similar responsiveness and stability, and in some cases, better than PIE.

Evaluating the L4S Architecture in Cellular Networks with a Programmable Switch

“…Their objective is to fight bufferbloat for any type of traffic rather than to distinguish the LL traffic from the classic traffic. Assuming that programmable traffic management at the data plane can lead to great benefits for QoS, the authors of [18] implement in P4 the PI2 AQM [19] for reducing queuing delay. They proved that implementing a modern AQM in P4 is not tricky and requires only basic bit manipulations at the data plane.…”