Heavy traffic resource pooling in parallel-server systems
Queueing Systems: Theory and Applications
Commissioned Paper: Telephone Call Centers: Tutorial, Review, and Research Prospects
Manufacturing & Service Operations Management
Optimal control of parallel server systems with many servers in heavy traffic
Queueing Systems: Theory and Applications
Scheduling Flexible Servers with Convex Delay Costs in Many-Server Service Systems
Manufacturing & Service Operations Management
| Hi-index | 0.00 |
We consider scheduling and routing control problems for queueing models with I customer classes and J server pools, each consisting of many statistically identical, exponential servers. Customers require a single service that can be performed by a server from one of the pools; the service rate is μij ≥ 0, which depends on the customer's class i and the server's pool j, and customers can abandon the system while waiting to be served. In the heavy traffic regime of Halfin and Whitt, these problems are formally equivalent to I-dimensional diffusion control problems. We analyze the diffusion control problems is two special cases. First, when the service rates depend only on the pool (μij = μj), the diffusion control problem is shown to be similar to (but distinct from) the diffusion control problem for a single class model, which greatly reduces the complexity of the problem. Second, when the service rates depend only on the class (μij = μi), the diffusion control problem is shown to be equivalent to a diffusion control problem for a single pool model, a problem that has previously been studied. In the first case, we also establish a rigorous relation between the queueing control problem and the diffusion control problem, showing that a policy for the queueing model, based on an ordinary differential equation of Hamilton-Jacobi-Bellman type, is asymptotically optimal.