Reducing the acknowledgement frequency in IETF QUIC

Abstract

Satellite networks usually use in-network methods (such as Performance Enhancing Proxies for TCP) to adapt the transport to the characteristics of the forward and return paths. QUIC is a transport protocol that prevents the use of in–network methods. This paper explores the use of the recently–standardised IETF QUIC protocol with a focus on the implications on performance when using different acknowledgement policies to reduce the number of packets and volume of bytes sent on the return path. Our analysis evaluates a set of ACK policies for three IETF QUIC implementations, examining performance over cellular, terrestrial and satellite networks. It shows that QUIC performance can be maintained even when sending fewer acknowledgements, and recommends a new QUIC acknowledgement policy that adapts QUIC's ACK Delay value based on the path RTT to ensure timely feedback. The resulting policy is shown to reduce the volume/rate of traffic sent on the return path and associated processing costs in endpoints, without sacrificing throughput.