Global Synchronization Protection for Bandwidth Sharing TCP Flows in High-Speed Links

TL;DR

This paper introduces a simple, scalable extension to TCP queue management called global synchronization protection (GSP) that effectively prevents flow synchronization issues in high-speed links, improving link utilization.

Contribution

The paper presents GSP, a minimalistic and efficient queue management extension that suppresses flow synchronization without complex mechanisms, suitable for high-speed and low-power hardware.

Findings

GSP effectively prevents global synchronization in TCP flows.

GSP performs comparably to complex AQM schemes like CoDel and PIE.

GSP is scalable and suitable for high-speed, low-power hardware implementations.

Abstract

In a congested network link, synchronization effects between bandwidth-sharing TCP flows cause wide queue length oscillations, which may translate into poor link utilization if insufficiently buffered. We introduce global synchronization protection (GSP), a simple extension to the ordinary operation of a tail-drop queue that safely suppresses the flow synchronization. Our minimalistic solution is well suited for scaling with leading-edge link rates: it adds only few extra operations in the fast path and does not require accelerated memory access compared to the line rate. GSP makes it easier to provide advanced control of TCP congestion in high-speed links and in low-power packet processing hardware. Using experiments with a Linux prototype of GSP, we show that, despite its exclusive focus on removing global synchronization, the new scheme performs as well as far more complex active queue management (AQM) schemes like CoDel and PIE.