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

Reviewer: Kevin Hofstra

1. What is the best way of allocating the limited resources of the internet in a non-cooperative environment? Is there a way of creating a pricing scheme that will not create too much additional overhead? What is necessary in terms of fairness, especially when different streams are using different pricing schemes?
2. A proposal to solve the distribution of resources while creating a pricing scheme and continuing to ensure fairness.
3. A. The problem of achieving the system optimum is composed into two subproblems:

i. Network problems

ii. User problems

The optimum is achieved when users’ choices of charges and the network’s choice of allocated rates are in equilibrium.

2. To maximize the objective function given the current prices per unit flow, a user only needs to know the price per unit flow. Users with TCP can computer their prices per unit flow without any help from the network. They do not need to know the price at each resource.
3. Fairness is guaranteed because the price that a user pays for using resources is proportional to its rate.
4. As the number of users increases, the rates at Nash equilibrium points converge to the system optimal rates.

4. Critique the main contribution
• Significance- 3 Although the integration of pricing and fairness is seen as a step forward many of the details are still in a theoretic stage. I don’t see this being implemented without further studies.
• Convincing- 2 .The evidence is largely theory based. The equations seem to work correctly but have not been tested in a real environment. They limited their analysis to a simple single bottleneck. It is extremely questionable if a user could predict the effect of their parameters in a larger and more complicated network.
5. System researchers and builders should recognize that the term fairness, even though not defined in the non-cost TCP world, is even more ambiguous in the pricing rate world. How we should charge people and what should be considered fair is an issue that may not be solvable. This seems to reduce the issue of allowing each user to maximize their flows according to the allowable conditions.