Blocking When Service Is Required From Several Facilities Simultaneously

Ward Whitt

AT&T Technical Journal · 1985 · 306 citations · 59 references

Concepts

TL;DR

The system consists of multiple multiserver facilities with no waiting space, where several customer classes arrive as independent Poisson processes, and although exact blocking expressions exist, they are complex. The paper seeks to determine the blocking probability for each customer class and investigates approximation schemes. Customers request one server from each of a class‑dependent subset of facilities; service starts only if all required servers are free, otherwise the customer is blocked and lost.

Abstract

This paper analyzes a mathematical model of a blocking system with simultaneous resource possession. There are several multiserver service facilities without extra waiting space at which several classes of customers arrive in independent Poisson processes. Each customer requests service from one server in each facility in a subset of the service facilities, with the subset depending on the customer class. If service can be provided immediately upon arrival at all required facilities, then service begins and all servers assigned to the customer start and finish together. Otherwise, the attempt is blocked (lost without generating retrials). The problem is to determine the blocking probability for each customer class. An exact expression is available, but it is complicated. Hence, this paper investigates approximation schemes.

References

59