Are HTTP/2 Servers Ready Yet?

Superseding HTTP/1.1, the dominating web protocol, HTTP/2 promises to make web applications faster and safer by introducing many new features, such as multiplexing, header compression, request priority, server push, etc. Although a few recent studies examined the adoption of HTTP/2 and evaluated its impacts, little is known about whether the popular HTTP/2 servers have correctly realized the new features and how the deployed servers use these features. To fill in the gap, in this paper, we conduct the first systematic investigation by inspecting six popular implementations of HTTP/2 servers (i.e., Nginx, Apache, H2O, Lightspeed, nghttpd and Tengine) and measuring the top 1 million Alexa web sites. In particular, we propose new methods and develop a tool named H2Scope to assess the new features in those servers. The results of the large-scale measurement on HTTP/2 web sites reveal new observations and insights. This study sheds light on the current status and the future research of HTTP/2.