Research On ATM Access And IP Switching

ABSTRACTAt present, communications networks are evolving to be digital, broadband. andintegrated services networks. Asynchronous Transfer Mode (ATM) is a neu'infrastructure of multipIexing and switching, and is proposed by ITU-T to adapt sucha trend. It can support simultaneously voice, data, video, and multimedia serilices. soit is an ideal pIatform of backbone network to transfer broadband and multimediainfOrmation. Today, ATM technology specifications have been matured and a series ofproducts have been put on the market. But ATM network has not been able to supportenough services and new aPplications, which prevents it from popularizing anddeveloping. Though Internet can not guarantee the bandwidth and QoS. it has beenab1e to provide abundant information and services. So il has been grow'ingexponential1y for some time. In the circumstances, two impetuses to ATM developingare providing convenient and cheaP access to ATM network and supporting IP overATM network. Consequently the research in the dissertation includes four parts. Inpartl a two-stage queuing model for ATM User Access Equipment with trafficshaping and multiplexing functions is proposed, and is anaIyzed in detail usingmultiple on-off sources and fluid flow method. Part2 deals wtith the design andimplementation of an ATM User Access Equipment, which can be applied as B-UAE(Broadband User Access Equipment) or ISADM (lntegrated Services Add/DropMultiplexer). Descriptions of all methods of IP over ATM presently known arepresented in part3, besides the perfOrmance of IP switching is simulated, and somesuggestions which can improve the performance of IP switching are given. Based onoptimal utilization of the system resources, Part4 proposes a new approach by \\.hichthe flow classification parameter X and flow deIetion deIay D will be automaticaIl}'adjusted. The algorithrn is simple to implement, and simulation shows the algorithmis efficient and able to balance the resources utilization of IP switching.Chapterl describes the features, architecture and protocol reference model ofATM network. The research results on ATM both in China and abroad are introduced.The successes and problems of ATM are pointed out.Chapter2 presents a two-stage queuing model of ATM User Access Equipmentx',ith traffic shaping and muItiplexing fiJnctions, and analyses the queuing model indetail using multiple on-off sources and fluid flow method. Sets of performancecurves, incIuding lost probability and average waiting time, are gained. By making acomparison between the multiplexer with traffic shaping and that \vithout trat11cshaping, it is discussed how the traffic shaping effect on the performance of ATMmultiplexer and selection the output speed of traffic shaper. The results show that thetraffic shaping can reduce the lost probability and the storage needed.ln chapter3, lhe design and implementation of an ATM User Access Equipmentare studied, and its structure, principle and key technologies to be solved aredescribed. The equipment, which has local switching function and mu1tiple STM-linterfaces, can be applied as B-UAE or ISADM. lt consists of synchIonous serx-iceadaptation moduIe, asynchronous service adaptation module, muItiplexing moduleand line module to support voice, video and data services. Many kinds of interfaces such as El, Px64K, 8K circuit emulation services interfaces and RJ45 Ethernet service interface, are offered. Also the communication protocol used between modules in the equipment is presented.Chapter4 describes all kinds of methods of IP over ATM currently known,including CIPOA (Classical IP Over ATM), LANE (LAN Emulation), MPOA, IPa. switching and MPLS.In chapter5, the principle of IP switching, GSMP and IFMP are described, and some suggestions that can improve the performance of IP switching are given. The approach combines the simplicity, scalability, and robustness of IP with the high speed, large capacity and supporting...