[Bloat] Fwd: Identifying TCP congestion control algorithms, and measurement results

[Otto Solares]

On Wed, Mar 23, 2011 at 08:13:08AM -0700, Stephen Hemminger wrote:
> This showed up on the end-to-end mailing list and might be of interest
> to this group. It is interesting how many hosts are still using BIC
> (probably RHEL/Centos 5). BIC is known to be broken and unfair.

Too those "web servers use abnormal slow start algorithms" could be
related to sites using IW10 or more for the initial cwnd:

http://blog.benstrong.com/2010/11/google-and-microsoft-cheat-on-slow.html

IW10 seems to be part now of mainline Linux since 2.6.37:

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=356f039822b8d802138f7121c80d2a9286976dbd
-
 Otto

> From: Lisong Xu <lisongxu2 at gmail.com>
> Date: Tue, Mar 15, 2011 at 3:36 PM
> Subject: [e2e] Identifying TCP congestion control algorithms, and
> measurement results
> 
> 
> Greetings,
> 
> We have recently developed a tool, called TCP Congestion Control
> Avoidance Identification (CAAI), for actively identifying the TCP
> congestion avoidance algorithm of a remote web server. We used CAAI to
> measure the TCP algorithms of the top 5000 web sites in February 2011,
> and got some preliminary results in which you might be interested.
> 
> # Only 16.85~25.58% of web servers still use the traditional AIMD.
> # 14.36%, 15.82%, and 14.33% of web servers use BIC, CUBIC' (kernel
> 2.6.25 and before), and CUBIC (kernel 2.6.26 and after), respectively.
> Total = 44.51%.
> # 9.97% and 0.30~9.03% of web servers use CTCP' (Windows Server 2003
> and XP Pro x64) and CTCP (Windows Server 2008, Vista, and 7),
> respectively. Interestingly, CTCP' behaves very similar to HSTCP.
> Total = 10.27~19%.
> # Some web servers use non-default TCP algorithms (such as YEAH), some
> web servers use some unknown TCP algorithms which are not available in
> any major operating system family, and some web servers use abnormal
> slow start algorithms.
> 
> More information is available at our project webpage
> http://cse.unl.edu/~xu/research/TCPcensus.html.
> 
> Thanks
> Lisong
> 
> --
> Lisong Xu, Associate Professor
> Computer Science & Engineering
> University of Nebraska-Lincoln
> http://cse.unl.edu/~xu