Performance analysis & traffic modelling in broadband integrated services digital networks

Broadband Integrated Services Digital Networks (B-ISDN) will provide the ability to support a wide range of services using Asynchronous Transfer Mode (ATM) as the transfer technique. While ATM provides the flexibility to integrate a large number of services economically, the challenge to teletraffic engineers is to ensure that an acceptable grade of service is provided for each type of traffic. Research in network performance and traffic modelling is required to develop network operating strategies which will meet these goals. This thesis is mainly concerned with performance analysis models for B-ISDN. In performance modelling of access nodes, several strategies are studied for mixing loss-sensitive traffic with delay-sensitive traffic in both TDM and ATM environments. The performance of these strategies are analysed by different methods. Next, the problem of statistical multiplexing of interactive data, interactive images and variable bit rate (VBR) video traffic in an ATM access node is considered. In this situation, the effect of link rate to source rate ratio and also the effect of priority encoding of the VBR video on the performance of the ATM access node are studied. Next, a strategy is proposed for statistically multiplexing a range of constant bit rate services with an aggregate of variable bit rate services at an ATM access node. Performance parameters for both service types are evaluated by analysis and also by simulation. Accurate source models are an essential component of any access node problem. The traffic generated from video services will greatly influence the overall performance and data requirements in B-ISDN, and the next area considered in this thesis is modelling of video traffic. Several video models in the literature are reviewed and a few models based on the concept of hidden Markov models are examined for modelling variable bit rate video traffic. Network performance based on these models is investigated. Another area that is covered in this thesis is performance modelling for those parts of the network that are subject to traffic with periodically varying rates. A computational probability analysis is presented for queues with cyclo-stationary arrivals and/or cyclo-stationary service rates. Such traffic patterns may arise in a variety of telecommunication and computer networks, including B-ISDN.