[e2e] Identifying TCP congestion control algorithms, and measurement results

Lisong Xu lisongxu2 at gmail.com
Tue Mar 15 15:36:33 PDT 2011


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


Lisong Xu, Associate Professor
Computer Science & Engineering
University of Nebraska-Lincoln

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