Paper review: < Analysis and Design of an Adaptive Virtual Queue (AVQ) Algorithm for Active Queue Management [SS01] >

Reviewer: <Ryan Gehl>

1. State the problem the paper is trying to solve.

The purpose of this paper is to study three properties of Adaptive Virtual Queue (AVQ) schemes. These properties include: (1) stability in the presence of feedback delays, (2) its ability to maintain small queue lengths, and (3) its robustness in the presence of extremely short flows.

2. 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? 

The main contribution of this paper is to propose a simple and easy to implement AVQ algorithm that only relies on keeping track of the virtual queue size without actually enqueuing or dequeuing packets.

3. Summarize the (at most) 3 key main ideas (each in 1 sentence.) 

(1) Active Queue Management (AQM) schemes are used by routers to intelligently select packets to mark (or drop) in a manner that conveys information about the current state of the network to the users.
(2) (1) The implementation complexity of AVQ is comparable to RED, (2) AVQ is primarily a rate-based marking, (3) AVQ regulates utilization, (4) AVQ adapts the capacity of the virtual queue, and (5) the deired utilization and damping variables can be adjusted to determine the stability of the system.
(3) The authors ran five simulation experiments to test their AVQ algorithm under various conditions.

4. Critique the main contribution
   • Rate the significance of the paper on a scale of 5 (breakthrough), 4 (significant contribution), 3 (modest contribution), 2 (incremental contribution), 1 (no contribution or negative contribution). Explain your rating in a sentence or two.

   I would rate this paper as a 4 because this paper does present a deployable AQM algorithm known as AVQ. This algorithm, which is an extension of previous work in the field of AQM, performs better than a number of other well-known AQM schemes.

   • Rate how convincing the methodology is: how do the authors justify the solution approach or evaluation? Do the authors use arguments, analyses, experiments, simulations, or a combination of them? Do the claims and conclusions follow from the arguments, analyses or experiments? Are the assumptions realistic (at the time of the research)? Are the assumptions still valid today? Are the experiments well designed? Are there different experiments that would be more convincing? Are there other alternatives the authors should have considered? (And, of course, is the paper free of methodological errors.)

   To justify their results, the authors run five simulation experiments under various conditions to show that their algorithm performed better than exisitng AQM algorithms. In section 4 of this paper, the authors derive a lengthy proof of their underlying assumption. I found the authors' approach to be a solid and concise one.

   • What is the most important limitation of the approach?

   One limitation of their approach is that this algorithm, I believe, would be succeptable to attacks by malicious users (as would all AQM algorithms).

5. What lessons should researchers and builders take away from this work. What (if any) questions does this work leave open?

One lesson researchers should take away from this work is that good research often comes in the form of studying current solutions to open problems and extending them in a simple or novel way.