非同步傳輸網路SSCOP協定之效能分析與模擬評估

Abstract

服務指定連接導向協定(SSCOP; Service Specific Connection- Oriented Protocol)目前被使用作為非同步傳輸模式(ATM)適應層( Adaptation Layer)的通訊協定，其功能為連接導向數據通訊及寬頻整合 服務數位網路中UNI/NNI控制訊號之傳送。SSCOP是一種新的通訊協定，通 訊協定參數(如視窗(window)大小､計數器(timers))和使用環境(如錯誤/ 遺失機率､往返延遲( round trip delay))之間的關係尚未被深入的探討 。現有的文獻提出一些方法去找尋這些關係，不過是基於訊框(frame)錯 誤機率很低的情形所求得。在本論文中，我們提出一種趨近分析的方法去 求得結果，並且假設是在訊框錯誤機率較高的情形下。最後推導出在已知 的環境和參數設定下，預測最大輸出量效率(throughput efficiency)的 公式。 這個公式對於如何去選擇適當的通訊協定參數，因而使SSCOP能有 良好的效能將有助益的。透過程式模擬結果與比較，可以看出我們所提出 的分析和模擬結果有良好的一致性。 Service Specific Connection-Oriented Protocol(SSCOP) is now being studied foruse as the ATM Adaptation Layer Protocol for connection oriented data communication and UNI/NNI signaling in the B-ISDN. SSCOP is a new protocolstandard for which the relationships between protocol parameters(e.g., thewindow size, timers) and the environment(e.g., the error/loss rate, the roundtrip delay) have not yet been explored in detail. Previous works have proposedsome approaches to find these relationships. The results obtaind are under oneassumption that the frame error rate is low. In this thesis, we proposed anapproximate analysis to find the relationships under a degraded environmentwhich may have higher frame error rate, and derived a performance equations topredict the maximum throughput efficiency of SSCOP based on the given environment and parameter settings. The equations is valuable for choosing appropriate protocol parameters to allow SSCOP to operate at high performance. A comparison through simulation shows that our approximate analysis is in goodagreement with the simulation results.