異質性網路下兼具公平及品質服務之管理機制

Abstract

在現行網路環境下，資料傳送多數是利用TCP/IP的方式來傳送，而在網路環境下，會有不同版本的TCP同時存在於網路環境中，另外除了TCP 以外，還有許多不具TCP Flow Control 特性的流量，我們統稱這類流量為TCP Unfriendly Flow，如UDP(User Datagram Protocol) ，本論文主要針對現行較常用的TCP版本Reno 與 Vegas，研究其二者在同時存在於網路環境下，利用隨機提前棄置RED(Random Early Detection)機制,來加以控制其頻寬分配，並依據其機制下，提出針對流量數(Flow)來控制緩衝區(Buffer)大小的管理機制，使得Reno 與 Vegas的TCP流量,可以公平分配頻寬，之後在利用公平權重佇列WFQ (Weight Fair Queuing) ，考慮當TCP 與 UDP同時存在網路環境時，可依據設定給TCP及UDP不同的比率，來分配其有限的頻寬，在利用RED處理TCP部份的公平性問題，之後在加入WFQ處理控制UDP的頻寬佔有，可使得其網路環境有公平及有效的頻寬管理機制，為此論文主要之研究目的。

In the current networking environment, TCP/IP is the most popular transmission method for data communication. However, there exist different TCP versions on the Internet. Besides TCP, many other control protocols whose characteristics are not like TCP are called TCP Unfriendly Flow in general, such as UDP (User Datagram Protocol). This thesis mainly focuses on fairness problem between the frequently used TCP versions, Reno and Vegas. By adjusting buffer size dynamically according to the active flow number, our method uses the active queue management scheme, RED (Random Early Detection), to fairly allocate the bottleneck bandwidth. WFQ (Weighted Fair Queuing) is also used to allocate bandwidth by the ratio of TCP and UDP flows when considering their coexistence on the Internet. The primary propose of the thesis is to solve the fairness problem by adjusting RED buffer size and to control the bandwidth allocation between TCP and UDP by deploying WFQ.