Upgrading to HTTP/2

Dawn Parzych

Upgrading to HTTP/2

HTTP/2 is fast approaching its first anniversary, at which point browser support for SPDY will be deprecated. Instart Logic has provided SPDY support since 2014. We want to ensure our customers that have been enjoying faster pages with SPDY continue getting optimum performance, so we have enabled HTTP/2 on the Instart Logic CDN. We are happy to announce HTTP/2 support is currently in beta and will be generally available in the coming weeks.

Content to end users will be delivered over either HTTP/2 or HTTP/1.1, depending on your users' browser support, irrespective of your server configuration. End users will see the benefits of HTTP/2 without your organization needing to make infrastructure changes.

HTTP2 and Instart Logic

I enabled HTTP/2 on a site that's being routed through Instart Logic. The following waterfalls compare a set of page elements being downloaded via HTTP/1.1 versus HTTP/2:





The parallel requests in HTTP/2 results in the following improvements:

Version HTTP/1.1 HTTP/2
Start Render 2.985 2.398
Speed Index 4672 2543

Switching to HTTP/2 translates to a 20% improvement in start render time and a 45% improvement in speed index.

Before switching to HTTP/2, we recommend you read this overview of HTTP/2 compatibility with front end optimization techniques with front end optimization techniques. Changing to HTTP/2 may make some optimizations you might have previously implemented obsolete.

Once you have made the switch to HTTP/2, proper debugging, troubleshooting and validation tools are needed. Here are four to get you started:

  1. Wireshark: Wireshark added decoding in version 1.12.0.
  2. HTTP/2 indicator

    HTTP/2 indicator: This Chrome extension won't help debug, but it is nice to see the blue lighting bolt indicating your site is being served by HTTP/2. Clicking on the indicator opens Chrome Net internals in a new tab.

  3. Chrome Net Internals: For debugging purposes, Chrome Net Internals displays live HTTP/2 sessions with detailed information on sessions and frames. This can be accessed by clicking on the blue lightning bolt from above or by entering "chrome://net-internals/#http2" into the Chrome browser.

    Chrome Net Internals

  4. HTTP/2 with Curl: Curl has had an -http2 option since September 2013. Using the verbose option provides additional details on the use of HTTP/2 for a request.

To take advantage of all that HTTP/2 has to offer, contact your account manager or support.

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