HTTP2 Expression of Interest: Alibaba


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


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


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.


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.



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

Received on Sunday, 15 July 2012 16:13:14 UTC