Buffer and server allocation in general multi‐server queueing networks

Abstract

This paper deals with the joint optimization of the number of buffers and servers, an important issue since buffers and servers represent a significant amount of investment for many companies. The joint buffer and server optimization problem (BCAP) is a non-linear optimization problem with integer decision variables. The performance of the BCAP is evaluated by a combination of a two-moment approximation (developed for the performance analysis of finite general-service queues) and the generalized expansion method (a wellknown method for performance analysis of acyclic networks of finite queues). A standard non-linear optimization package is used to optimize the BCAP for a large number of experiments. A comprehensive set of numerical results is presented. The results show that the methodology is capable of handling the trade-off between the number of servers and buffers, yielding better throughputs than previously published studies. Also, the importance of the squared coefficient of variation of the service time is stressed, since it strongly influences the approximate optimal allocation.

Optimal Server Allocation to Parallel Queueing Systems by Computer Simulation

“…Similar to Case MG in Table 3, multiple rows in the rightmost columns in Table 5 show the weighted average system times with 5, 30 and 50 replications. With 50 replications, the allocation (8,10) shows the optimal for the case. Table 7 shows the results for Case GG, where the inter-arrival time distributions are not exponential and the service time distributions are not exponential either.…”

“…al. [8] tried to optimize the number of buffers and servers in a setting of restricted M/G/c/K queueing networks, in the way that the resulting throughput is greater than a predefined threshold throughput. Alexandros et.…”

Finite Queueing Modeling and Optimization: A Selected Review

“…It is worthwhile to mention that if = 0, the above problem reduces to the pure BAP and if = 1, the pure CAP is obtained. The BCAP1 problem was treated in details by Woensel et al [43], when the joint optimization of the number of buffers and servers was firstly solved by means of Powell's [39] method, a classical nonlinear derivative-free optimization algorithm, while a two-moment approximation and the GEM compute the performance measure of interest (the throughput). The proposed methodology was capable of handling the trade-off between the number of servers and buffers, yielding better throughput than previously published studies.…”

Buffers and Servers Allocation in General Finite Queueing Networks

“…As such, this perspective is more general than the first objective function formulation. A discussion on this multiobjective formulation can be found in the paper by van Woensel et al [17], Cruz et al [3,4].…”