Paper review : TCP Vegas: End to End Congestion Avoidance on a Global Internet (BP95)
Reviewer : Hai Fang (firstname.lastname@example.org)
To provide a TCP implementation, Vegas, which has a better throughput and
lower losses than the existing TCP implementations, e.g., Reno.
This paper introduced several techniques for improving TCP, including a new
timeout mechanism, a novel approach to congestion avoidance that tries to
control the number of extra buffers the connection occupies in the network,
and a modified slow-start mechanism.
All these techniques are implemented as TCP Vegas, and comprehensive
experimental results are presented.
- Main ideas
- TCP Vegas, which adopts several advanced techniques, has a good performance,
as shown by the experimental results.
- All the changes Vegas made are confined on the sending side.
- Vegas' increased throughput is not a result of its taking bandwidth away from
Reno connections, but due to a more efficient utilization of the bottleneck link.
- Significance rating: 3
This paper provides an excellent implementation of TCP. (4)
The affect of this paper on the industrial field aftermath is not as good as
- Convincing rating
The paper provides a comprehensive experimental performance study, using both
simulations and measurements on the Internet, of the Vegas and the Reno
implementations of TCP. The author also discuss other properties, e.g.,
fairness, stability, queue behavior, etc., by extra experiments.
This paper doesn't provide a theoretical analysis of the good performance of
TCP Vegas. Nevertheless, this shortcoming has been overcome in a recent paper
"Understading TCP Vegas: A Duality Model" [LPW01].
Another limitation, somehow unreasonable, is that the TCP Vegas (or maybe even a
particular technique among the ones proposed in the paper?) has not been
adopted by the Internet standard or by the industrial products.
A new implemetation need to be compatible with the current implemetations,
especially the over-whelming standard, whereas the latter is at the same time
a good criterion of the former wrt the performance or other comparable