Paper review: Congestion Avoidance and Control

Reviewer: Jie Zhou

Previous implementation of Internet transport protocol has severe congestion problems. This paper analyzes the cause of these
problems and describes several new algorithms to overcome them.

The three key main ideas of this paper are:
1. Slow-start algorithm starts the data flowing by gradually increasing the amount of data in-transit at appropriate speed.
2. A good estimator of round trip time should consider the variation, which increases quickly with load, and should use exponential
scheme when a packet has to be retransmitted more than once.
3. Additive increase / multiplicative decrease policy is suitable for congestion avoidance.

I rate the paper's significance as significant contribution(4), because it sovles the threat of Internet collapse due to inappropriate
transport protocol implementation. Within recent years, Internet is developing at a dramatic speed. Now, almost every business or
family is involved in Internet. If it collapse, the whole world's economy will be damaged severely. So it is very important to insure
Internet's stability.

With both theoretical analysis and scientific data from actual experiments, the paper is very convincing to the readers, who could come to
undersand the realistic module of Internet transport via this paper.

The author left one approach open: control congestion from the gateway side. This approach has the potential benefit of fairly sharing the
network capacity among hosts.