HTTP2 Expression of Interest: Alibaba

Joshua Zhu <zhuzhaoyuan@gmail.com> Sun, 15 July 2012 16:14 UTC

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Date: Mon, 16 Jul 2012 00:12:46 +0800
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From: Joshua Zhu <zhuzhaoyuan@gmail.com>
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Subject: HTTP2 Expression of Interest: Alibaba
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Hi,

This is Alibaba's response to the call for expression of interest in HTTP/2.0.

Alibaba
-------

Alibaba Group [1] runs the largest e-commerce group in Asia and has
four websites listed on Alexa's Top 100 Sites list: taobao.com (#14),
tmall.com (#61), alibaba.com (#74), alipay.com (#93).

We have our own CDN infrastructure which has pretty heavy traffic (the
peak of last year was about 900Gbits/sec and it is expected to be
about 2Tbits/sec this year).

We are developing a web server [2] based on the Nginx HTTP server.


SPDY
----

Basically, we like the SPDY idea, but with the following exceptions:

1) Mandating use of TLS

We strongly disagree with this requirement, because it causes problems:

*) SSL certificates are not cheap, especially for small websites or
those located in a developing country. We are from a developing
country (China), and we know this well.

*) Encryption and decryption require more hardware investment and for
some content types, for instance, images, it's meaningless to
encrypt/decrypt them.

*) It's difficult to implement and deploy for proxy/cache software
since it's neither secure nor feasible to deploy many certificates on
the proxy who acts as a middle man.

We believe it should be optional.

2) Mandating compression of HTTP headers

This will introduce overhead for HTTP server software, for instance, a
load balancer may have to decompress a full packet to tell which
'Host' a stream is flowing to.

We think it should be modified to allow server to pick out the 'Host'
more easily.


HTTP Speed+Mobility & draft-tarreau-httpbis-network-friendly-00
---------------------------------------------------------------

We have not evaluated these two proposals yet.


Conclusion
----------

We think the SPDY spec should be modified. Now we are looking into the
SPDY implementation of Nginx. We'll test it and share our results once
it's production ready.


[1] http://en.wikipedia.org/wiki/Alibaba_Group
[2] http://tengine.taobao.org


Regards,

--
Joshua Zhu
Senior Software Engineer
Server Platforms Team at Taobao, Alibaba Group

HTTP2 Expression of Interest: Alibaba Joshua Zhu