具擴充性及多點播送能力的非同步傳輸模式交換鍵之設計及效能分析

Abstract

在本論文中，我們設計並分析一個具擴充性及多點播送能力的非同步傳輸 模式交換鍵。 我們所設計的小封包路由控制及競爭解決方式是分散在許 多交換單元上，而且整個交換 鍵具有模組化架構，所以它能擴充成較大 的交換鍵。在兩級之間，它使用區域訊息傳遞 方式，因而可以很方便地 處理訊號同步的問題。由於本架構具規則性及制式性，使之具 有較高 VLSI整合密度。全部輸出埠是以群為單位分割，使在同一群的輸出埠可以 共享路 由路徑。另外群的路由安排方式也減少了所需的交換單元。我們 用一個兩級的交換鍵架 構來說明設計理念。採用更多的級數，將可以很 容易地擴充交換鍵的大小。我們用M/Geom/1模式分析了小封包遺失率、延 遲時間、平均佇列長度及輸出率。實驗數據不但證明我們所提出的非同步 傳輸模式交換鍵不論在單點播送或多點播送都能滿足非同步傳輸網路的效 能需求，而且也比其他同類型交換鍵使用較少的交換單元及造成較少的延 遲時間。 In this thesis, we design and analyze a growable multicast ATM switch. It can grow to a large size since both cell routing and contention resolution are designed to distribute over switch elements, and the switch structure is modular.It is easy for synchronization of signals by using local communications between stages. It has high VLSI integrationdensity due to a regular and uniform structure. The output ports are partitioned into groupsto permit sharing of routing paths. The concept of group routing helps reduce an order of magnitude of switch elements. A two-stage switch architecture is described to illustrate ourdesign principle. The switch can be easily expanded to a larger size by usingmore stages. The performance analysis of the switch in terms of cell loss rate,cell delay,mean queue length, mean waiting time, and throughput is conducted using the M/ Geom/1 model. Experimental results show that the proposed ATM switch not only meets the ATM performance requirements either for unicasting ormulticasting but also uses fewer switch elements and has less delay than othercomparable switches.