https://jherbots.info/ Latest stuff from Joris Herbots' personal website! http://www.rssboard.org/rss-specification python-feedgen en-US Sat, 03 Aug 2024 16:13:44 +0000 https://jherbots.info/#link-research For HTTP/2 and HTTP/3, multiple (Web page) resources are loaded by multiplexing them onto a single TCP or QUIC connection. A "prioritization system" is used to properly schedule the order in which the resources are sent. As HTTP/2's "prioritization tree" underperformed, a more straightforward setup called the Extensible Prioritization Scheme (EPS) was proposed for HTTP/3. This paper represents the first real-world measurement study into how this new scheme is supported and employed in practice by the three main browser engines and 12 different popular servers and cloud/CDN deployments. We find considerable heterogeneity in overall EPS (sub)feature support and even fundamental differences in approach/philosophy between the stacks. As incorrect prioritization can have a negative effect on (Web) performance metrics, our work not only provides essential insights for browser vendors and server deployments but also offers recommendations for future improvements. h3-eps-in-the-wild Sat, 20 Jul 2024 09:00:00 +0200 https://jherbots.info/#link-research In the HTTP Adaptive Streaming (HAS) paradigm, client-side Adaptive Bitrate (ABR) algorithms drive the (quality-variant) scheduling and downloading of media segments. These ABR algorithms are implemented in the application layer and can therefore base their logic only on relatively coarse and/or inaccurate application-layer metrics. The recently standardized QUIC transport protocol has many userspace implementations, which paves the way for cross-layer optimizations by exposing transport-layer metrics to application-layer algorithms. In this paper, we investigate whether the availability of fine-grained transport-level throughput metrics can positively impact the operation of ABR algorithms and hence the Quality of Experience (QoE) of HAS users. Our results show that QUIC-level throughput data can indeed aid ABR algorithms to more accurately predict playout buffer underruns, which in turn allows the ABR algorithm to take reactive measures in a timely fashion such that playback stalls can be avoided under challenging network conditions. cross-that-boundary Sat, 08 Jul 2023 09:00:00 +0200 https://jherbots.info/#link-research Assessing media streaming performance traditionally requires the presence of reproducible network conditions and a heterogeneous dataset of media materials. Setting up such experiments represents a complex challenge in itself. This challenge becomes even more complex when we consider the new QUIC transport protocol, which has many tunable features, yet is difficult to analyze due to its inherent encrypted nature. In this paper, we introduce Vegvisir, which aims to solve these aforementioned challenges by providing an open-source automated testing framework for orchestrating media streaming experiments over HTTP/3. We describe how users can steer the behavior of Vegvisir through its configuration system. We provide a high-level overview of its inner workings and its broad applicability by describing two use cases: one covering sizeable experiments spanning multiple days and another covering HAS evaluation scenarios. vegvisir Sat, 08 Jul 2023 09:00:00 +0200