Learning HTTP/2

Foreword

In 2009, HTTP/1.1 was well over a decade old, and arguably still the most popular application protocol on the internet. Not only was it used for browsing the web, it was the go-to protocol for a multitude of other things. Its ease of use, broad implementation, and widely shared understanding by developers and operation engineers gave it huge advantages, and made it hard to replace. Some people were even starting to say that it formed a “second waist” for the classic hourglass model of the internet’s architecture.

However, HTTP was showing its age. The web had changed tremendously in its lifetime, and its demands strained the venerable protocol. Now loading a single web page often involved making hundreds of requests, and their collective overhead was slowing down the web. As a result, a whole cottage industry of Web Performance Optimization started forming to create workarounds.

These problems were seen clearly in the HTTP community, but we didn’t have the mandate to fix them; previous efforts like HTTP-NG had failed, and without strong support for a proposal from both web browsers and servers, it felt foolish to start a speculative effort. This was reflected in the HTTP working group’s charter at the time, which said:

The Working Group must not introduce a new version of HTTP and should not add new functionality to HTTP.

Instead, our mission was to clarify HTTP’s specification, and (at least for me) to rebuild a strong community of HTTP implementers.

That said, there ...