Modeling the interactions of congestion control and switch scheduling

8 years 4 months ago
Modeling the interactions of congestion control and switch scheduling
—In this paper, we study the interactions of user-based congestion control algorithms and router-based switch scheduling algorithms. We show that switch scheduling algorithms that were designed without taking into account these interactions can exhibit a completely different behavior when interacting with feedbackbased Internet traffic. Previous papers neglected or mitigated these interactions, and typically found that flow rates reach a fair equilibrium. On the contrary, we show that these interactions can lead to extreme unfairness with temporary flow starvation, as well as to large rate oscillations. For instance, we prove that this is the case for the MWM switch scheduling algorithm, even with a single router output and basic TCP flows. We also show that the iSLIP switch scheduling algorithm achieves fairness among ports, instead of fairness among flows. Finally, we fully characterize the network dynamics for both these switch scheduling algorithms.
Alexander Shpiner, Isaac Keslassy
Added 13 May 2011
Updated 13 May 2011
Type Journal
Year 2011
Where CN
Authors Alexander Shpiner, Isaac Keslassy
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