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題名 | The Evaluation of Allocation for End-to-end Quality of Service Requirement=端點服務品質需求分配之評估 |
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作者姓名(中文) | 黃一泓; 王仁澤; 李乾麟; 朱泰峰; | 書刊名 | 修平學報 |
卷期 | 1 2000.09[民89.09] |
頁次 | 頁243-264 |
分類號 | 448.6 |
關鍵詞 | 服務品質; 網路傳輸; Guaranteed service; Scheduling; Local QOS allocation; Traffic shaper; |
語文 | 英文(English) |
中文摘要 | 未來的高速網路必須提供不同等級的服務品質(quality of service),來滿足各種網路應用程式的需求。比如,傳送視訊的網路應用程式,就必須滿足達到某種資料遺失率(packet loss ratio)的要求, 而網路視訊會議(video conference)則需要滿足即時傳送(real time transmission)的要求。 一個使用者所關心的是它的應用程式在網路傳輸時,整條連線(end-to-end)的服務品質。對於如何將整個連線的需求,對應到區域性的每個交換節點的需求,並且藉以提昇網路的使用率,則是網路提供者所需考量的問題。因此,在此一部份,我們主要探討連線延遲分配的問題。我們使用(σ, ρ)交通模式(traffic model),來描述應用程式的交通,進而導出延遲上限(delay bound)與連線個數(the number of connection)的關係式。我們發現使用不同的分配策略(allocation policy)會導致不同的網路效能。除此之外,我們也發展了一個評估模式來分析不同的分配策略,利用兩個不同的網路拓樸(network topology),我們比較公平分配法(equal allocation)與完美分配法(optimal allocation)的差異,以及證明了分配策略的正確性與有效性。 |
英文摘要 | In this paper, we focus on the problem of translating a global QOS (quality of service) requirement into a set of local QOS requirement. Applications with guaranteed service would like to acquire an end-to-end delay bound from the network. In the literature, most researches only attempt to solve the worse case delay bound suffered by a connection passed through a series of switching nodes. Simply, they equally allocate the excess delay or reserve the same bandwidth in each switch along the path. However, if the network can apply a tighter delay bound than the applications want, and the excess delay amount can be adequately distributed into the local switches along the path, applications can get the best possible performance. It motivates us to propose a novel local QOS requirement allocation scheme to get better performance which is abbreviated by the supportable connection number. We proposed an analysis model to evaluate the allocation scheme in a series of switching nodes with the rate-controlled scheduling architecture, including a traffic shaper and a nonpreemptive earliest-deadline-first scheduler. With the number of maximum allowable connections as the performance index, we derived an optimal delay allocation policy. The numerical results have shown the importance of allocation policy and the factors that affect the performance index. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。