Of the Utmost Importance: Resource Prioritization in HTTP/3 over QUIC

Abstract

Not even five years after the standardization of HTTP/2, work is already well underway on HTTP/3. This latest version is necessary to make optimal use of that other new and exiting protocol: QUIC. However, some of QUIC’s unique characteristics make it challenging to keep HTTP/3’s functionalities on par with those of HTTP/2. Especially the efforts on adapting the prioritization system, which governs how multiple resources can be multiplexed on a single QUIC connection, have led to some difficult to answer questions. This paper aims to help answer some of those questions by being the first to provide experimental evaluations and result comparisons for 11 different possible HTTP/3 prioritization approaches in a variety of simulation settings. We present some non-trivial insights, discuss advantages and disadvantages of various approaches, and provide results-backed actionable advice to the standardization working group. We also help foster further experimentation by contributing our complete HTTP/3 implementation, results dataset and custom visualizations to the community.