Join the Shortest Queue with Many Servers. The Heavy-Traffic Asymptotics

We consider queueing systems with n parallel queues under a Join the Shortest Queue (JSQ) policy in the Halfin-Whitt heavy-traffic regime. We use the martingale method to prove that a scaled process counting the number of idle servers and queues of length exactly two weakly converges to a two-dimens...

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Bibliographic Details
Main Authors: Eschenfeldt, Patrick Clark, Gamarnik, David
Other Authors: Massachusetts Institute of Technology. Operations Research Center
Format: Article
Published: Institute for Operations Research and the Management Sciences (INFORMS) 2019
Online Access:http://hdl.handle.net/1721.1/120946
https://orcid.org/0000-0003-4865-7645
https://orcid.org/0000-0001-8898-8778
Description
Summary:We consider queueing systems with n parallel queues under a Join the Shortest Queue (JSQ) policy in the Halfin-Whitt heavy-traffic regime. We use the martingale method to prove that a scaled process counting the number of idle servers and queues of length exactly two weakly converges to a two-dimensional reflected Ornstein-Uhlenbeck process, while processes counting longer queues converge to a deterministic system decaying to zero in constant time. This limiting system is comparable to that of the traditional Halfin-Whitt model, but there are key differences in the queueing behavior of the JSQ model. In particular, only a vanishing fraction of customers will have to wait, but those who do incur a constant order waiting time. Keywords: queueing theory; parallel queues; diffusion models