Poster: Reverse-Path Congestion Notification: Accelerating the Congestion Control Feedback Loop

Ralf Kundel, Nehal Baganal Krishna, Christoph Gärtner, Tobias Meuser, Amr Rizk

Abstract: Congestion control mechanisms in computer networks rely mainly on a feedback loop having a reaction time equal to the flow RTT. Reducing this feedback time helps the sender to react faster to changing network conditions such as congestion. In this work, we propose reverse-path congestion notification on top of programmable networking switches. Our approach can significantly lower the reaction time, such that the congestion control implementation can adapt much faster to changing network conditions. The proposed approach aims to work with current TCP implementations with no required changes to the communication endpoints. Last, we show how the presented approach could be realized by utilizing off-the-shelf programmable switches.