A queueing system with on-demand servers: local stability of fluid limits

Lam M. Nguyen, Alexander L. Stolyar

Research output: Contribution to journalArticlepeer-review


We study a system where a random flow of customers is served by servers (called agents) invited on-demand. Each invited agent arrives into the system after a random time; after each service completion, an agent returns to the system or leaves it with some fixed probabilities. Customers and/or agents may be impatient, that is, while waiting in queue, they leave the system at a certain rate (which may be zero). We consider the queue-length-based feedback scheme, which controls the number of pending agent invitations, depending on the customer and agent queue lengths and their changes. The basic objective is to minimize both customer and agent waiting times. We establish the system process fluid limits in the asymptotic regime where the customer arrival rate goes to infinity. We use the machinery of switched linear systems and common quadratic Lyapunov functions to approach the stability of fluid limits at the desired equilibrium point and derive a variety of sufficient local stability conditions. For our model, we conjecture that local stability is in fact sufficient for global stability of fluid limits; the validity of this conjecture is supported by numerical and simulation experiments. When local stability conditions do hold, simulations show good overall performance of the scheme.

Original languageEnglish (US)
Pages (from-to)243-268
Number of pages26
JournalQueueing Systems
Issue number3-4
StatePublished - Aug 1 2018


  • Common quadratic Lyapunov function
  • Dynamic system stability
  • Fluid limit
  • On-demand server invitations
  • Queueing networks
  • Switched linear systems

ASJC Scopus subject areas

  • Statistics and Probability
  • Computer Science Applications
  • Management Science and Operations Research
  • Computational Theory and Mathematics


Dive into the research topics of 'A queueing system with on-demand servers: local stability of fluid limits'. Together they form a unique fingerprint.

Cite this