Paper Review: Charge-Sensitive TCP and Rate Control in the Internet

Reviewer: Kenneth Chin

The Internet is a heterogenous network where users are competing with resources, for example bandwidth. Such an noncoporative environment gives rise to inefficient and unfair bandwidth allocation among users. In view of this problem, people are working on different pricing mechanisms, whose main goal is either to punish malicious users or to encourage good user behavior by means of incentives. However, many of the pricing mechanisms require feedback from routers along the way in order to regulate the transmission rate. This approach is thought to be not good because feedback may be lost or incorrect. In this paper, the author proposed a new scheme called the Charge-Sensitive TCP which is a window-based algorithm of TCP Vegas.

According to the analysis, Charge-Sensitive TCP scheme works well in a cooperative environment where users are well behaving. It achieves the system optimal rates. However, the analysis is not necessarily representing the Internet where different versions of TCP are floating around. Apparently, Charge-Sensitive TCP scheme only works on TCP Vegas because it makes use of the target queue size as a parameter and this is exactly the fundamental working principal of TCP Vegas. Second, Charge-Sensitive TCP scheme has a poor efficiency and fairness in bandwidth allocation under noncooperative environment and small number of users. Although it is said that it would be approaching the system optimal rates as the number of users are growing, it leads to another problem of how to encourage people to use the new scheme.

All in all, this paper is good. It is a 2nd grade paper.