FDDI 網路效能分析與模擬

Abstract

FDDI 是一個以 ring 為架構，使用光纖作為傳輸介質，而能提供 100 Mbps 速度，並連結各種電腦與週邊設備的通訊網路系統。FDDI MAC 層的 通訊協定中的優先權架構支援兩種類型的服務：同步與非同步。同步的訊 息必須要能夠保證即時的資料傳送，而非同步的訊息必須要有合理效能和 使用率。在這篇論文中，我們使用平均值方式，由小而大地改變進入網路 的訊息流量，以分析同步和非同步訊息的效能。利用這種分析方式，也能 夠導出平均 token 繞轉 FDDI 網路一圈的時間。本分析含蓋三個部份： “單一優先權、對稱系統”、“多重優先權、對稱系統”與“多重優先權 、非對稱系統”。最後，我們將討論電腦模擬的結果，並與分析的結論作 比較。 FDDI network provides an 100 Mbps communication system to interconnect computers and peripheral equipments using fiber optics as the transmission medium in a ring configuration. The FDDI MAC priority mechanism supports two classes of services: synchronous and asynchronous. The synchronous traffic must guarantee a real time transmission, and the asynchronous traffic should have a reasonable throughput and channel utilization. In this thesis, we use a mean value approach to analyze the mean throughput of both synchronous and asynchronous traffics while the message arrival rate is varying from a very low value to a high value. Using this analysis, we can also derive the mean token rotation time. This analysis is composed of three parts: "single priority, symmetric system", "multiple priority, symmetric system" and "multiple priority, asymmetric system". Lastly, the simulation results is presented, and it will be compared with our analysis results.