Sharding and HTTP/2 connection reuse revisited

ACM Internet Measurement Conference (IMC), pp. 292–301

Abstract

HTTP/2 and HTTP/3 avoid concurrent connections but instead multiplex requests over a single connection. Besides enabling new features, this reduces overhead and enables fair bandwidth sharing. Redundant connections should hence be a story of the past with HTTP/2. However, they still exist, potentially hindering innovation and performance. Thus, we measure their spread and analyze their causes in this paper. We find that 36% - 72% of the 6.24 M HTTP Archive and 78% of the Alexa Top 100k websites cause Chromium-based webbrowsers to open superfluous connections. We mainly attribute these to domain sharding, despite HTTP/2 efforts to revert it, and DNS load balancing, but also the Fetch Standard.

Authors 4

1. Constantin Sander Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Aachen, Germany

   RWTH Aachen, University, Aachen, Germany

2. Leo Blöcher Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Aachen, Germany

   RWTH Aachen, University, Aachen, Germany

3. Klaus Wehrle Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Aachen, Germany

   RWTH Aachen, University, Aachen, Germany

4. Jan Rüth Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Aachen, Germany

   RWTH Aachen, University, Aachen, Germany