الفهرس | Only 14 pages are availabe for public view |
Abstract Asynchronous transfer mode (A TM) is a streamlined protocol with minimal error and flow control capabilities; this reduces the overhead of processing ATM cells and reduces the number of overhead bits required with each cell, thus enabling ATM to operate at high data rates. Further, its use of fixed-size cells simplifies the processing required at each ATM node, again supporting the use of ATM at high data rates. So, the ATM has been deemed the transfer technique of choice in an Integrated environment supporting various multimedia services. Multlmedia connections carrying several different classes of traffic will have a wide variety of demands for quality of service (QoS). On the other hand, networl< utilization is a primary concern to the network provider. Thus, effective control mechanisms are necessary to maintain a belanoe between QoS and network utilization, both at the time of call setup and during the progress of the calls across the ATM network. These include connection admission control (CAC), usage parameter control (UPC-policing), and network resource management. The main objective of this thesis is to address the problem of designing an effective CAC algorithm. In this thesis, a proposed CAC with increasing priority based on waijing time of each call is introduoed. The proposed admission controller tries to satisfy the QoS of higher priority calls and, in the same time, avoid the problem of highly-repeated rejections of lower priority ones, which is encountered in other methods. Also, the proposed admission policy tries to satisfy the QoS requirements of the admitted calls not only at the cell level but also at the call level. |