一個在ATM網路上多對一ABR服務之合併點演算法

Abstract

在ATM網路上，ABR(Available Bit Rate)服務提供極小的細胞遺失率及可 依據網路上的流量而動態地配置頻寬。ABR服務可以被分類為四種類型: 一對一連接、一對多連接、多對一連接，以及多對多連接。 目前，大部分的研究致力於一對一及一對多連接的ABR服務。然而，多對一連接的ABR服務只有少部分的研究。在多對一連接ABR服務中，來自不同分支的流量在經過合併點後會被合併為一stream。也就是所有的服務流量將會使用相同的VPI/VCI。這導致了一些議題。其中的一個議題是速率配置演算法。大部分現存的研究集中在提供一個有效又公平，而且可以從現存的演算法延展而來的速率配置演算法。此外，另一個議題是合併點演算法。 在此篇論文中, 我們提出一個可以減少在網路上的RM(Resource Management)細胞數且又可同時保持有效率且公平特性的合併點演算法。此外, 我們所提出的演算法可與現存的任一種速率配置演算法一起共同運作。我們也經由數值分析來評估此演算法以及經由模擬來驗證此數值分析的正確性。

In ATM networks, ABR services provide small cell loss rate and dynamic bandwidth allocation for data traffic according to traffic load in the network. ABR services can be classified in four classes: point-to-point connection, point-to-multipoint connection, multipoint-to-point connection, or multipoint-to-multipoint connection. Considerable efforts have been devoted in point-to-point and point-to-multipoint ABR services. However, few studies have addressed the issues of multipoint-to-point ABR service. In multipoint-to-point ABR service, traffic from multiple branches is merged into the same stream after passing the merging point, i.e., all traffic will use the same VPI/VCI. This results in some issues. One of these issues is the rate allocation algorithm. Most of the existing studies focus on providing an effective and fair rate allocation algorithm, which can be extended from the existing algorithms. Besides, another issue is the merging point algorithm. In this thesis, we propose a merging point algorithm that can reduce the number of resource management (RM) cells in the network and keep the efficiency and fairness. Besides, our proposed algorithm can incorporate with any existing multipoint-to-point rate allocation algorithm. We also evaluate our algorithm through numerical analysis and verify it through simulations.