[e2e] a question about the deployment of SACK TCP

[Mark Claypool]

Ron Lee writes:
 > Only 5% of the TCP connections actually use SACK, (From Anja
 > Feldmann, trace from 12/99) according to
 > http://www.icir.org/floyd/sack-questions.html of October 2000.  Is
 > there an up-to-date answer to this? What fraction of the
 > bytes/packets/TCP-flows in the Internet are SACK-capable?

Our analysis of some data gathered from a commercial broadband
provider in Fall 2003 shows about 90% of the flows are SACK-enabled.
Further analysis suggests that SACK significantly reduces the number
of retransmissions compared to the non-SACK enabled flows.  More
details can be found in:

  Todd DeSantis and David Loose. "TCP Traffic Analysis", Major
  Qualifying Project MQP-MLC-MT03, Computer Science Department, Fall
  2003. Sponsored by Motorola. (Advisors Mark Claypool and Robert
  Kinicki) Online at: http://www.cs.wpi.edu/~claypool/mqp/motorola/

Mark 

------------------------------------------------------------------------
 Mark Claypool        CS Associate Professor        claypool at cs.wpi.edu
   Worcester Polytechnic Institute   http://www.cs.wpi.edu/~claypool/