Student: W.H.Chuang Advisor: M.C.Liang

Department of Electrical Engineering

Kaohsiung Polytechnic Institute

In network transmission, bandwidth remains is the most important network resources. The distribution as well as the segmentation of bandwidth will directly affect the network resources as well as the service quality. How to effectively allocate bandwidth for information transmission, i.e., the choice of transfer modes, is one of the most important factors that affects the network resources. In current telephone systems, the Synchronous Transfer Mode (STM) is used. The data is transferred using predefined network bandwidth. Whether the user uses the channel to transfer data or not, it will occupied the same bandwidth in STM approach. As a result, there are significant amount of idle bandwidth wasted in this approach. However, in the operation of Asynchronous Transfer Mode (ATM), a dynamic bandwidth allocation is used, the bandwidth efficiency is much higher than STM approach. If a service needs smaller bandwidth at certain time, a small amount of bandwidth is allocated. If a service needs larger bandwidth, a large amount of bandwidth can be dynamically allocated. As a result, ATM is best suited for integrating different communication service networks used today. ATM is accepted by ITU-T as the major transmission technology standard for B-ISDN network applications.

In this thesis, STM and ATM technologies are compared. In this study, it shows that ATM has much better transmission characteristics than STM in wide bandwidth variation services such as multimedia.