When Heavy-tailed and Light-tailed Flows Compete


Jayakrishnan U. Nair


Centrum Wiskunde and Informatica
Stochastics Group
Science Park 123
1098 XG Amsterdam
The Netherlands


Monday, 20 January 2014, 11:30 to 12:30



Abstract: This talk focuses on the design and analysis of scheduling policies for multi-class queues, such as those found in wireless networks and high-speed switches.  In this context, we study the response time tail under generalized max-weight policies in settings where the traffic flows are highly asymmetric. Specifically, we consider a setting where a bursty flow, modeled using heavy-tailed statistics, competes with a more benign, light-tailed flow. In this setting, we prove that classical max-weight scheduling, which is known to be throughput optimal, results in the light-tailed flow having heavy-tailed response times. However, we show that via a careful design of inter-queue scheduling policy (from the class of generalized max-weight policies) and intra-queue scheduling policies, it is possible to maintain throughput optimality, and guarantee light-tailed delays for the light-tailed flow, without affecting the response time tail for the heavy-tailed flow.