IDEAS home Printed from https://ideas.repec.org/a/eee/ejores/v321y2025i2p462-475.html
   My bibliography  Save this article

Asymptotically optimal routing of a many-server parallel queueing system with long-run average criterion

Author

Listed:
  • Cao, Ping
  • Zhong, Zhiheng

Abstract

This paper considers a parallel queueing system with multiple stations, each of which contains many statistically identical servers and has a dedicated queue. Upon each customer arrival, the system manager must decide to which station the customer should be routed, with the objective of minimizing the system’s long-run average delay cost. One feature of this paper is that a customer’s delay cost depends not only on his/her delay, but also on the routed station. Considering this heterogeneity across stations, we propose a routing policy, which can be regarded as an extension of the MED–FSF policy. Under this policy, any arriving customer will be routed to: (i) the station with the minimum value, which depends on the station’s expected delay and the station index when servers in all stations are fully occupied; or otherwise (ii) the station with a fastest idle server. Using asymptotic analysis, we derive diffusion limits of queue-length processes and their stationary distributions under the proposed policy in the Halfin–Whitt regime. Combined with an asymptotic lower bound result for the long-run average delay cost, we show that the proposed routing policy is asymptotically optimal under the considered objective. Finally, we provide numerical experiments to validate the accuracy of our diffusion approximation, and we compare the performance metrics under the proposed policy with those under other commonly used routing policies.

Suggested Citation

  • Cao, Ping & Zhong, Zhiheng, 2025. "Asymptotically optimal routing of a many-server parallel queueing system with long-run average criterion," European Journal of Operational Research, Elsevier, vol. 321(2), pages 462-475.
  • Handle: RePEc:eee:ejores:v:321:y:2025:i:2:p:462-475
    DOI: 10.1016/j.ejor.2024.09.044
    as

    Download full text from publisher

    File URL: http://www.sciencedirect.com/science/article/pii/S0377221724007471
    Download Restriction: Full text for ScienceDirect subscribers only

    File URL: https://libkey.io/10.1016/j.ejor.2024.09.044?utm_source=ideas
    LibKey link: if access is restricted and if your library uses this service, LibKey will redirect you to where you can use your library subscription to access this item
    ---><---

    As the access to this document is restricted, you may want to search for a different version of it.

    References listed on IDEAS

    as
    1. Itay Gurvich & Ward Whitt, 2009. "Queue-and-Idleness-Ratio Controls in Many-Server Service Systems," Mathematics of Operations Research, INFORMS, vol. 34(2), pages 363-396, May.
    2. Down, Douglas G. & Lewis, Mark E., 2006. "Dynamic load balancing in parallel queueing systems: Stability and optimal control," European Journal of Operational Research, Elsevier, vol. 168(2), pages 509-519, January.
    3. Wu, Rong & Down, Douglas G., 2009. "Round robin scheduling of heterogeneous parallel servers in heavy traffic," European Journal of Operational Research, Elsevier, vol. 195(2), pages 372-380, June.
    4. Rami Atar & Adam Shwartz, 2008. "Efficient Routing in Heavy Traffic Under Partial Sampling of Service Times," Mathematics of Operations Research, INFORMS, vol. 33(4), pages 899-909, November.
    5. Yue Hu & Carri W. Chan & Jing Dong, 2022. "Optimal Scheduling of Proactive Service with Customer Deterioration and Improvement," Management Science, INFORMS, vol. 68(4), pages 2533-2578, April.
    6. Shlomo Halfin & Ward Whitt, 1981. "Heavy-Traffic Limits for Queues with Many Exponential Servers," Operations Research, INFORMS, vol. 29(3), pages 567-588, June.
    7. Niyirora, Jerome & Zhuang, Jun, 2017. "Fluid approximations and control of queues in emergency departments," European Journal of Operational Research, Elsevier, vol. 261(3), pages 1110-1124.
    8. J. Michael Harrison & Assaf Zeevi, 2004. "Dynamic Scheduling of a Multiclass Queue in the Halfin-Whitt Heavy Traffic Regime," Operations Research, INFORMS, vol. 52(2), pages 243-257, April.
    9. Mor Armony & Avishai Mandelbaum, 2011. "Routing and Staffing in Large-Scale Service Systems: The Case of Homogeneous Impatient Customers and Heterogeneous Servers," Operations Research, INFORMS, vol. 59(1), pages 50-65, February.
    10. Melanie Rubino & Barış Ata, 2009. "Dynamic Control of a Make-to-Order, Parallel-Server System with Cancellations," Operations Research, INFORMS, vol. 57(1), pages 94-108, February.
    11. Junfei Huang & Boaz Carmeli & Avishai Mandelbaum, 2015. "Control of Patient Flow in Emergency Departments, or Multiclass Queues with Deadlines and Feedback," Operations Research, INFORMS, vol. 63(4), pages 892-908, August.
    12. Itay Gurvich & Ward Whitt, 2009. "Scheduling Flexible Servers with Convex Delay Costs in Many-Server Service Systems," Manufacturing & Service Operations Management, INFORMS, vol. 11(2), pages 237-253, June.
    13. Mor Armony & Amy R. Ward, 2010. "Fair Dynamic Routing in Large-Scale Heterogeneous-Server Systems," Operations Research, INFORMS, vol. 58(3), pages 624-637, June.
    14. Amy R. Ward & Mor Armony, 2013. "Blind Fair Routing in Large-Scale Service Systems with Heterogeneous Customers and Servers," Operations Research, INFORMS, vol. 61(1), pages 228-243, February.
    15. Tolga Tezcan & J. G. Dai, 2010. "Dynamic Control of N -Systems with Many Servers: Asymptotic Optimality of a Static Priority Policy in Heavy Traffic," Operations Research, INFORMS, vol. 58(1), pages 94-110, February.
    16. Zhong, Zhiheng & Cao, Ping, 2023. "Balanced routing with partial information in a distributed parallel many-server queueing system," European Journal of Operational Research, Elsevier, vol. 304(2), pages 618-633.
    17. Noah Gans & Ger Koole & Avishai Mandelbaum, 2003. "Telephone Call Centers: Tutorial, Review, and Research Prospects," Manufacturing & Service Operations Management, INFORMS, vol. 5(2), pages 79-141, September.
    18. Li Xia & Zhe George Zhang & Quan‐Lin Li, 2022. "A c/μ‐Rule for Job Assignment in Heterogeneous Group‐Server Queues," Production and Operations Management, Production and Operations Management Society, vol. 31(3), pages 1191-1215, March.
    19. Hung, Ying-Chao & PakHai Lok, Horace & Michailidis, George, 2022. "Optimal routing for electric vehicle charging systems with stochastic demand: A heavy traffic approximation approach," European Journal of Operational Research, Elsevier, vol. 299(2), pages 526-541.
    20. Ragavendran Gopalakrishnan & Sherwin Doroudi & Amy R. Ward & Adam Wierman, 2016. "Routing and Staffing When Servers Are Strategic," Operations Research, INFORMS, vol. 64(4), pages 1033-1050, August.
    21. Itai Gurvich & Ward Whitt, 2010. "Service-Level Differentiation in Many-Server Service Systems via Queue-Ratio Routing," Operations Research, INFORMS, vol. 58(2), pages 316-328, April.
    22. Jinsheng Chen & Jing Dong & Pengyi Shi, 2020. "A survey on skill-based routing with applications to service operations management," Queueing Systems: Theory and Applications, Springer, vol. 96(1), pages 53-82, October.
    23. Zhenghua Long & Nahum Shimkin & Hailun Zhang & Jiheng Zhang, 2020. "Dynamic Scheduling of Multiclass Many-Server Queues with Abandonment: The Generalized cμ / h Rule," Operations Research, INFORMS, vol. 68(4), pages 1128-1230, July.
    24. Pascal Moyal & Ohad Perry, 2022. "Stability of Parallel Server Systems," Operations Research, INFORMS, vol. 70(4), pages 2456-2476, July.
    25. Tolga Tezcan, 2008. "Optimal Control of Distributed Parallel Server Systems Under the Halfin and Whitt Regime," Mathematics of Operations Research, INFORMS, vol. 33(1), pages 51-90, February.
    26. Cao, Ping & Zhong, Zhiheng & Huang, Junfei, 2021. "Dynamic routing in a distributed parallel many-server service system: The effect of ξ-choice," European Journal of Operational Research, Elsevier, vol. 294(1), pages 219-235.
    27. Avishai Mandelbaum & Petar Momčilović & Yulia Tseytlin, 2012. "On Fair Routing from Emergency Departments to Hospital Wards: QED Queues with Heterogeneous Servers," Management Science, INFORMS, vol. 58(7), pages 1273-1291, July.
    28. Jeunghyun Kim & Ramandeep S. Randhawa & Amy R. Ward, 2018. "Dynamic Scheduling in a Many-Server, Multiclass System: The Role of Customer Impatience in Large Systems," Manufacturing & Service Operations Management, INFORMS, vol. 20(2), pages 285-301, May.
    Full references (including those not matched with items on IDEAS)

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Noa Zychlinski, 2023. "Applications of fluid models in service operations management," Queueing Systems: Theory and Applications, Springer, vol. 103(1), pages 161-185, February.
    2. Zhong, Zhiheng & Cao, Ping, 2023. "Balanced routing with partial information in a distributed parallel many-server queueing system," European Journal of Operational Research, Elsevier, vol. 304(2), pages 618-633.
    3. Jinsheng Chen & Jing Dong & Pengyi Shi, 2020. "A survey on skill-based routing with applications to service operations management," Queueing Systems: Theory and Applications, Springer, vol. 96(1), pages 53-82, October.
    4. Cao, Ping & Zhong, Zhiheng & Huang, Junfei, 2021. "Dynamic routing in a distributed parallel many-server service system: The effect of ξ-choice," European Journal of Operational Research, Elsevier, vol. 294(1), pages 219-235.
    5. Jinsheng Chen & Jing Dong, 2024. "Managing flexibility: optimal sizing and scheduling of flexible servers," Queueing Systems: Theory and Applications, Springer, vol. 108(3), pages 415-474, December.
    6. Amy R. Ward & Mor Armony, 2013. "Blind Fair Routing in Large-Scale Service Systems with Heterogeneous Customers and Servers," Operations Research, INFORMS, vol. 61(1), pages 228-243, February.
    7. Adan, Ivo J.B.F. & Boon, Marko A.A. & Weiss, Gideon, 2019. "Design heuristic for parallel many server systems," European Journal of Operational Research, Elsevier, vol. 273(1), pages 259-277.
    8. Wyean Chan & Ger Koole & Pierre L'Ecuyer, 2014. "Dynamic Call Center Routing Policies Using Call Waiting and Agent Idle Times," Manufacturing & Service Operations Management, INFORMS, vol. 16(4), pages 544-560, October.
    9. Dongyuan Zhan & Gideon Weiss, 2018. "Many-server scaling of the N-system under FCFS–ALIS," Queueing Systems: Theory and Applications, Springer, vol. 88(1), pages 27-71, February.
    10. Dongyuan Zhan & Amy R. Ward, 2014. "Threshold Routing to Trade Off Waiting and Call Resolution in Call Centers," Manufacturing & Service Operations Management, INFORMS, vol. 16(2), pages 220-237, May.
    11. J. G. Dai & Tolga Tezcan, 2011. "State Space Collapse in Many-Server Diffusion Limits of Parallel Server Systems," Mathematics of Operations Research, INFORMS, vol. 36(2), pages 271-320, May.
    12. Mor Armony & Avishai Mandelbaum, 2011. "Routing and Staffing in Large-Scale Service Systems: The Case of Homogeneous Impatient Customers and Heterogeneous Servers," Operations Research, INFORMS, vol. 59(1), pages 50-65, February.
    13. Arapostathis, Ari & Pang, Guodong, 2019. "Infinite horizon asymptotic average optimality for large-scale parallel server networks," Stochastic Processes and their Applications, Elsevier, vol. 129(1), pages 283-322.
    14. Ragavendran Gopalakrishnan & Sherwin Doroudi & Amy R. Ward & Adam Wierman, 2016. "Routing and Staffing When Servers Are Strategic," Operations Research, INFORMS, vol. 64(4), pages 1033-1050, August.
    15. Carri W. Chan & Linda V. Green & Suparerk Lekwijit & Lijian Lu & Gabriel Escobar, 2019. "Assessing the Impact of Service Level When Customer Needs Are Uncertain: An Empirical Investigation of Hospital Step-Down Units," Management Science, INFORMS, vol. 65(2), pages 751-775, February.
    16. Jeunghyun Kim & Ramandeep S. Randhawa & Amy R. Ward, 2018. "Dynamic Scheduling in a Many-Server, Multiclass System: The Role of Customer Impatience in Large Systems," Manufacturing & Service Operations Management, INFORMS, vol. 20(2), pages 285-301, May.
    17. Petar Momčilović & Amir Motaei, 2018. "QED limits for many-server systems under a priority policy," Queueing Systems: Theory and Applications, Springer, vol. 90(1), pages 125-159, October.
    18. Merve Bodur & James R. Luedtke, 2017. "Mixed-Integer Rounding Enhanced Benders Decomposition for Multiclass Service-System Staffing and Scheduling with Arrival Rate Uncertainty," Management Science, INFORMS, vol. 63(7), pages 2073-2091, July.
    19. Alexander L. Stolyar & Tolga Tezcan, 2011. "Shadow-Routing Based Control of Flexible Multiserver Pools in Overload," Operations Research, INFORMS, vol. 59(6), pages 1427-1444, December.
    20. Zhenghua Long & Nahum Shimkin & Hailun Zhang & Jiheng Zhang, 2020. "Dynamic Scheduling of Multiclass Many-Server Queues with Abandonment: The Generalized cμ / h Rule," Operations Research, INFORMS, vol. 68(4), pages 1128-1230, July.

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:eee:ejores:v:321:y:2025:i:2:p:462-475. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: Catherine Liu (email available below). General contact details of provider: http://www.elsevier.com/locate/eor .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.