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

[Stephen Hemminger]

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.

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