Mind the delay: The adverse effects of delay-based TCP on HTTP

Neil Agarwal, Matteo Varvello, Andrius Aucinas, Fabián Bustamante, Ravi Netravali

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The last three decades have seen much evolution in web and network protocols: amongst them, a transition from HTTP/1.1 to HTTP/2 and a shift from loss-based to delay-based TCP congestion control algorithms. This paper argues that these two trends come at odds with one another, ultimately hurting web performance. Using a controlled synthetic study, we show how delay-based congestion control protocols (e.g., BBR and CUBIC + Hybrid Slow Start) result in the underestimation of the available congestion window in mobile networks, and how that dramatically hampers the effectiveness of HTTP/2. To quantify the impact of such finding in the current web, we evolve the web performance toolbox in two ways. First, we develop Igor, a client-side TCP congestion control detection tool that can differentiate between loss-based and delay-based algorithms by focusing on their behavior during slow start. Second, we develop a Chromium patch which allows fine-grained control on the HTTP version to be used per domain. Using these new web performance tools, we analyze over 300 real websites and find that 67% of sites relying solely on delay-based congestion control algorithms have better performance with HTTP/1.1.

Original languageEnglish (US)
Title of host publicationCoNEXT 2020 - Proceedings of the 16th International Conference on Emerging Networking EXperiments and Technologies
PublisherAssociation for Computing Machinery, Inc
Pages364-370
Number of pages7
ISBN (Electronic)9781450379489
DOIs
StatePublished - Nov 23 2020
Externally publishedYes
Event16th ACM Conference on Emerging Networking Experiment and Technologies, CoNEXT 2020 - Barcelona, Spain
Duration: Dec 1 2020Dec 4 2020

Publication series

NameCoNEXT 2020 - Proceedings of the 16th International Conference on Emerging Networking EXperiments and Technologies

Conference

Conference16th ACM Conference on Emerging Networking Experiment and Technologies, CoNEXT 2020
Country/TerritorySpain
CityBarcelona
Period12/1/2012/4/20

All Science Journal Classification (ASJC) codes

  • Computer Networks and Communications

Keywords

  • congestion control algorithm
  • HTTP
  • protocol design
  • TCP
  • web performance

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