Paper review: TCP Congestion Control witth a Misbehaving Receiver

Reviewer: Mike Liu

  1. State the problem the paper is trying to solve.
  2. The main problem the paper is trying to solve is trying to modify TCP to eliminate any incentive for a malicious Web client from misbehaving and driving a standard TCP sender arbitrarily fast.
  3. State the main contribution of the paper: solving a new problem, proposing a new algorithm, or presenting a new evaluation (analysis). If a new problem, why was the problem important? Is the problem still important today? Will the problem be important tomorrow?  If a new algorithm or new evaluation (analysis), what are the improvements over previous algorithms or evaluations? How do they come up with the new algorithm or evaluation? 
  4. The main contribution of the paper is that it provides a solution for modifying TCP to eliminate this type of undesirable behavior entirely, without requiring assumptions of any kind about receiver behavior. This problem is especially important because as the internet expands and grows to include more of the world, the potential for malicious users and misbehaving increases. In addition, since TCP accounts for 90 to 95% of the web traffic on the net. The potential to exploit any of the assumptions it makes is enormous and the effects could be devastating. It is best to solve these problems while disasters can be prevented. This problem will continue to be important tommorow as the Internet continues to impact all facets of our society. As more and more of society's services depend on the Internet, it will be essential that it remains secure and resilient to attacks and foul play.
  5. Summarize the (at most) 3 key main ideas (each in 1 sentence.) 
  6. The three 3 key main ideas are: (1) Three attacks on the congestion control mechanism of TCP that exploit a sender's vulnerability to non-conforming receiver behavior are: ACK division; DupACK spoofing; and Optimistic ACKing. (2) These three attacks have been implemented in a malicious version of TCP, named by the authors facetiously as: "TCP Daytona", and have demonstrated clear potential detrimental effects to TCP traffic in a network. (3) The design of TCP can be modified, without changing the nature of the congestion control function, using a new Cumulative Nonce approach, and implemented with sender-only modifications to allow immediate deployment, to eliminate these vulnerabilities.
  7. Critique the main contribution
  8. What lessons should researchers and builders take away from this work. What (if any) questions does this work leave open?
  9. The lessons researchers should take away from this work are that their is always potential assumptions in any implementation that can be exploited for malicious purposes. It is best to account for these early on so that the effects and possibilities of attacks can be minimized and prepared for. It is best to correct the system for such potential risks before it is widely deployed as TCP is, but if that is not done, at least they should correct for them before an attack actually happens, which this paper intended to do.