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Necessary condition for null controllability in many-server heavy traffic. (English) Zbl 1311.60108

Author’s abstract: Throughput sub-optimality (TSO), introduced in [R. Atar and G. Shaikhet, Ann. Appl. Probab. 19, No. 2, 521–555 (2009; Zbl 1221.60130)] for static fluid models of parallel queueing networks, corresponds to the existence of a resource allocation, under which the total service rate becomes greater than the total arrival rate. As shown in [R. Atar et al., Ann. Appl. Probab. 16, No. 4, 1764–1804 (2006; Zbl 1121.60092)] and [R. Atar and G. Shaikhet, loc. cit.], in the many-server Halfin-Whitt regime, TSO implies null controllability (NC), the existence of a routing policy under which, for every finite \(T\), the measure of the set of times prior to \(T\) at which at least one customer is in the buffer converges to zero in probability as the scaling limit. The present paper investigates the question whether the converse relation is also true, and TSO is both sufficient and necessary for the NC behaviour. In what follows, we do get the affirmation for systems with either of two customer classes (and possibly more service pools) or vice-versa and state a condition on the underlying static fluid model that allows the extension of the result to general structures.

MSC:

60K25 Queueing theory (aspects of probability theory)
90B22 Queues and service in operations research
90B36 Stochastic scheduling theory in operations research
60F05 Central limit and other weak theorems
93B05 Controllability
68M20 Performance evaluation, queueing, and scheduling in the context of computer systems

References:

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