Making Effective Use of HTTP/2 Server Push in Content Delivery Networks

Server Push, one of the most promising features of HTTP/2, allows web servers to speculatively send unsolicited web resources to clients. While the mechanism for Push is well defined, policies for effectively utilizing push to maximize page load performance are poorly understood. In this work we investigate the factors that should be considered when implementing a Push policy and combine them to propose an efficient Push policy geared for Content Delivery Networks. We test this policy on a set of real web pages and evaluate the impact of Push on their load times. Our results indicate that recommended Push configurations yield performance benefits of up to 27% for the pages we tested and avoid negative impact in all cases, whereas Push can have little or negative impact on page load speeds if used overly aggressively. We analyze the reasons that can lead to suboptimal Push performance and discuss ways to maximize its efficiency.