How to Beat FCFS

2026-08-12

AI Summary

This study addresses user queue selection in a two-queue competitive setting, where individuals choose based on expected waiting times. Integrating queuing theory and game theory, the paper analyzes how non–first-come-first-served (FCFS) service disciplines influence user routing behavior. It introduces a novel variant of last-come-first-served (LCFS) that constitutes a Nash equilibrium under low congestion and demonstrates that FCFS remains an equilibrium strategy even without commitment mechanisms. Furthermore, the work establishes a theoretical upper bound on the market share any alternative service discipline can capture against FCFS and constructs a non-FCFS policy capable of stably attracting a majority of users, thereby challenging the conventional dominance of FCFS.

Abstract

We study two observable queues with identical service rates, serving agents who arrive stochastically over time. Agents join the queue that minimizes their expected waiting time. Assuming one queue uses the ubiquitous First-Come-First-Served (FCFS) service rule, we show that by simply modifying its service order, the other queue can capture a strict majority of the demand. We establish an upper bound on the arrival share any rule can capture against FCFS. When both queues can design their service order, we show a novel variant of Last-Come-First-Served (LCFS) is an equilibrium in a low congestion regime. Without commitment, the picture changes, and there is an equilibrium where both queues use FCFS, and agents route to the queue with the shorter waitlist.

Problem

• queueing
• FCFS
• LCFS
• equilibrium
• service order

Innovation

• queueing strategy
• service discipline
• LCFS variant
• Nash equilibrium
• congestion regime