tailieunhanh - Hiệu suất của hệ thống thông tin máy tính P10

In practice, many systems consist of multiple, fairly independent service providing entities, each with their own queue. Jobs in such systems “travel” from queueing station to queueing station in order to complete. Instances of these so-called queueing networks can be observed at many places: in computer systems where a number of users are trying to get things done by a set of processors and peripherals | Performance of Computer Communication Systems A Model-Based Approach. Boudewijn R. Haverkort Copyright 1998 John Wiley Sons Ltd ISBNs 0-471-97228-2 Hardback 0-470-84192-3 Electronic Part III Queueing network models Performance of Computer Communication Systems A Model-Based Approach. Boudewijn R. Haverkort Copyright 1998 John Wiley Sons Ltd ISBNs 0-471-97228-2 Hardback 0-470-84192-3 Electronic Chapter 10 Open queueing networks IN the previous chapters we have addressed single queueing stations. In practice many systems consist of multiple fairly independent service providing entities each with their own queue. Jobs in such systems travel from queueing station to queueing station in order to complete. Instances of these so-called queueing networks can be observed at many places in computer systems where a number of users are trying to get things done by a set of processors and peripherals or in communication systems where packets travel via independent links and intermediate routers from source to destination. In fact in Chapter 4 we already saw an example of a queueing network the simple terminal model in which many system users attended a central processing system and their terminals in a cyclic manner. In this chapter we will elaborate in particular on the class of open queueing network models . queueing networks in which the number of customers is not a priori limited. We first introduce basic terminology in Section after which we discuss the class of feed-forward queueing networks in Section . This discussion provides us with a good insight into the analysis of more general open queueing networks such as Jackson networks in Section . Although Jackson queueing networks can be applied in many cases there are situations in which the model class supported does not suffice in particular when arrival streams are not Poisson and service times are not exponentially distributed. Therefore we present in Section an approximation procedure for large .