SPDY. In A Nutshell. Lightning. Namics.

Thomas Junghans. Senior Frontend Engineer. 31. August 2013

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(pronounced "SPeeDY")

SPDY in a Nutshell

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•  An Open Networking Protocol •  Developed mainly at Google •  Since July 2012 a defacto standard •  Basis for HTTP 2.0

What is SPDY?

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Reduce page loading time by 50% Improve web security Easy deployment - nothing to do for web authors

High Level Goals

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Allow many concurrent HTTP-Requests in one TCP session Reduce bandwidth by compressing headers Make SSL the underlying transport protocol

Technical Goals

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"We hope to engage the open source community to contribute ideas, feedback, code, and test results, to make SPDY the next-generation application protocol for a faster web." Chromium Dev-Team

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But why SPDY?

What's wrong with HTTP?

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Websites today are different from 10 years ago Webpages have become much much larger HTTP was not designed for latency

The Web has changed

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•  One request per connection •  In HTTP only the client can initiate a request •  Uncompressed request and response headers •  Redundant headers •  Data compression is optional

HTTP's Weaknesses

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SPDY extends HTTP

it does not replace it

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HTTP

SPDY

SSL

TCP

Application

Session

Presentation

Transport

SPDY extends the application layer as a session layer atop SSL

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Infinite Parallelism Request priorisation HTTP Header compression

SPDY Basic Features

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Unlimited concurrent streams over a single TCP connections are possible.

Infinite Parallelism means…

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Remember this?

Source: http://www.browserscope.org/?category=network&v=top

And this?

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CSS Sprites become obsolete, since as many icons and backgrounds as need be can be downloaded at the same time. Hostname sharding is unnecessary. No more hostnames for static resources.

You can forget those limitations

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First html, then js, then css please.

Request priorisation means

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Of course, that the headers are compressed Redundant headers such as the static User-Agent, Host, and Accept* are not resent with every request

Header Compression means

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SPDY provides server-initiated streams. This means content can be delivered to the client without the client asking for it.

SPDY Advanced Features

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Server Push – The client is informed that resources are going to be delivered. Server Hint – The client is informed that there are resources that should be requested.

Server-Initialized Streams

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Can we use SPDY today?

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Yes, we can

Seriously!!!

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Major sites such as Facebook, Twitter, Gmail, Wordpress already use SPDY. Test other sites with http://spdycheck.org/

Who uses SPDY?

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•  IE 11 J •  Firefox since V13 •  Chrome since V4 •  Safari n/a •  Opera since 12.1 •  Android Browsers and Opera Mobile

Browser-Support

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à https://isspdyenabled.com/

See if YOUR browser supports SPDY

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http://caniuse.com/spdy

Can I use SPDY?

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mod_spdy is a SPDY module for Apache 2.2 that allows your web server to take advantage of SPDY features https://developers.google.com/speed/spdy/mod_spdy/

Using SPDY with Apache

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Ruby SPDY - https://github.com/igrigorik/spdy node.js SPDY - https://github.com/indutny/node-spdy Jetty Web Server - http://wiki.eclipse.org/Jetty/Feature/SPDY

Other SPDY Servers

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You'll find usefull information on http://dev.chromium.org/spdy/spdy-best-practices

SPDY Best Practices

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That's all folks!

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•  http://dev.chromium.org/spdy/spdy-whitepaper •  http://dev.chromium.org/spdy/spdy-best-practices •  http://tools.ietf.org/html/draft-white-httpbis-spdy-analysis-00 •  https://hacks.mozilla.org/2012/02/spdy-brings-responsive-and-scalable-

transport-to-firefox-11/ •  http://stackoverflow.com/questions/4065344/is-spdy-really-used •  http://security.stackexchange.com/questions/29632/what-should-i-know-about-

spdy-before-enabling-it •  https://www.varnish-software.com/blog/why-i-dont-spdy •  http://www.wired.com/wiredenterprise/2013/03/facebook-spdy/ •  http://blog.liip.ch/archive/2012/06/21/this-site-now-runs-on-spdy.html

Sources & References