Performance Evaluation Of Switched Virtual Channel Based On Discrete Time Vacation Queue Theory

Along with the popularization of the Internet, user's requirement for bandwidth and QoS (Quality of Service) is improving. IP technology is famous for its agility and high efficiency in data exchanging among many network controlling methods, while ATM (Asynchronous Transfer Mode) can not only solve the problem of bandwidth, but also provide perfect QoS for IP, in addition, multimedia data, such as audio, image and video flow, can all be transferred on ATM. IP-over-ATM emerges as the times require. IP-over-ATM is based on SVC (Switched Virtual Channel), and the performance analysis and evaluation of SVC is precondition of IP-over-ATM technology research and development. According to SVC's operation mechanism, paralleling with SVC's performance analysis on continuous time queue theory, and conforming to digital technologies' development, a set of systemic discrete time delayed vacation queue models with Setup are built based on discrete time theory. Systemic researches on SVC's measurement evaluation are made by the method of theoretical analysis together with numerical examples and simulated experiments.Firstly, the work of SVC's performance analysis accomplished on continuous time are summarized and analyzed, a set of systemic queue models of SVC's performance analyses based on continuous time are abstracted as follows:M/G/l queue model with Setup/Close-Delay;M/G/1/K queue model with Setup/Close-Delay/Close-Down;MAP/G/1/A: queue model with Setup/Close-Delay/Close-Down;BMAP/G/1/A: queue model with Setup/Close-Delay/Close-Down. SVC performance measurements such as setup(release) ratio, utility ratio, idle ratio and cell's average waiting time under steady status are given.Secondly, aiming at memoryless property of cell arrival initiated by users, queue model Geom/G/1 with Setup/Close-Delay/Close-Down is built. Under steady state condition, SVC performance measurements such as cell average response time, setup(release) ratio, utilization ratio, and idle ratio, etc. are derived by the method of embedded Markov chain. Dependence relationship between these measurements anddelay timer, system load is shown through numerical examples and simulated experiments.Thirdly, considering cell bursty arrival, batch arrival mechanism is introduced and batch size % is supposed to be Pareto(c,a) distributed, a queue model GeomVG/1 withSetup/Close-Delay/Close-Down is built. Using embedded Markov chain method, analytic expressions of average response time and other SVC measurements such as setup(release) ratio, utility ratio, idle ratio etc. are derived. Furthermore, the influence of bursty arrival on SVC performance is shown by numerical examples and simulated experiments.Finally, considering correlation and bursty property of network traffic, cell arrival process is extended to D-BMAP(Discrete-Time Batch Markov Arrival Process), a queue model D-BMAP/G/1 with Setup/Close-Delay/Close-Down is built. A discrete time factorization principle with general vacation is proposed and proved. In the application with correlated and bursty arrival, steady state performance measurement analytic expressions of average response time, SVC setup(release) ratio, SVC utility ratio, SVC idle ratio etc. are derived, and some numerical examples are made to explain these formulae.