A QUIC Look Back: Longitudinal Internet-Scale Deployment and Transport Parameter Evolution

Authors: Marcel Kempf, Nikolas Gauder, Johannes Späth, Georg Carle, Johannes Zirngibl

Published in Proc. ACM Int. Measurement Conference (IMC), 2026

Abstract:
The Internet Engineering Task Force (IETF) specified QUIC in 2021, marking a significant shift in the Internet transport landscape. With its user-space implementation and flexible transport parameters, QUIC promised to enable rapid deployment of new extensions and features, fostering transport protocol innovation. While early stud- ies captured the initial surge of deployment, long-term evolution and maturation of the QUIC ecosystem remain largely unexplored. In this paper, we present a comprehensive longitudinal study of QUIC based on a five-year dataset of weekly Internet-wide scans from April 2021 to February 2026. We use fingerprinting to identify 22 distinct libraries and track their market share over time. Fur- ther, we analyze the diversity and evolution of transport parameter configurations and the adoption of new extensions. Our analysis reveals a steady growth in QUIC adoption across both IPv4 and IPv6. Additionally, we show that while the ecosystem is changing, a significant “long tail” of outdated drafts and default configurations persists. This work provides the first multi-year overview of the QUIC landscape, offering insights into its volatility, the speed of protocol updates in user space, and the use of QUIC’s flexible transport parameters on the Internet.

Recommended citation: Marcel Kempf, Nikolas Gauder, Johannes Späth, Georg Carle, Johannes Zirngibl, "A QUIC Look Back: Longitudinal Internet-Scale Deployment and Transport Parameter Evolution." Proc. ACM Int. Measurement Conference (IMC), 2026.