From: Jonas Lindberg (jonaslin@cs.washington.edu)
Date: Sun Oct 17 2004 - 19:24:28 PDT
Congestion Avoidance and Control
Van Jacobson
Reviewed by Jonas Lindberg:
In this paper, Jacobson describes five algorithms developed to improve the
BSD4 TCP after a series of congestion collapses in 1986. The algorithms
described are: round-trip-time variance estimation; exponential retransmit
timer backoff; slow-start; more aggressive receiver ack policy; and, dynamic
window sizing on congestion.
Jacobson's paper is interesting and well structured; I like that the author
starts with presenting the 'conservation of packets' principle, continues
with explaining how the old TCP-implementation was not following this
principle, and finally, suggests improvements and at the same time presents
results from tests of these improvements. Presenting the slow-start
algorithm separated from the congestion control algorithm was a good
structural choice that made things more clear (as Jacobson mentions).
Another thing that helps the readers understanding is the good use of
illustrations.
One weakness I see in the paper is that Jacobson often refers to in-progress
papers. It would have been better if he would have been able to refer to
published papers, but I realize that this sometimes is impossible. I also
think that Jacobson should have given a motivation rather than writing
"Without justification, I'll state that (.)" on page 321, paragraph 2.
I think the paper is relevant for me since it has provided me with a better
understanding of congestion problems and how the presented algorithms help
prevent congestion. Finding this paper relevant, I am still wondering if
there are not even more interesting papers from more recent research.
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