English  |  正體中文  |  简体中文  |  Items with full text/Total items : 2737/2828
Visitors : 3542151      Online Users : 30
RC Version 4.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
Scope Adv. Search
LoginUploadHelpAboutAdminister

Please use this identifier to cite or link to this item: http://ir.lib.stu.edu.tw:80/ir/handle/310903100/1254

Title: TCP Vegas於長距離網路傳輸公平性之研究
A Simulation Study on the Long Distance Network Transmission Fairness of TCP Vegas
Authors: 吳家振
Wu Chia-Chen
Contributors: 洪盟峰
Horng, Mong-Fong
資訊工程學系
Keywords: TCP Vegas;往返延遲時間;壅塞視窗
TCP Vegas;fairness;Round-Trip Time(RTT)
Date: 2008
Issue Date: 2011-05-24 15:12:02 (UTC+8)
Publisher: 高雄市:[樹德科技大學資訊工程學系]
Abstract: 目前在各種TCP壅塞控制演算法中,所被顧慮到常見的問題之一是網路流量公平性的議題,在討論頻寬分享公平性之問題的相關論文中[1, 2],所提出著名的TCP版本,像是TCP Tahoe與TCP Reno在長距離的網路環境中會遭遇到頻寬分享公平性的問題,尤其是當長距離連線經過廣域網路時所遭受的低吞吐量與低使用率的頻寬,無法比照短距離連線的效能。影響長距離TCP連線的因素是:(1)在長距離TCP連線的往返延遲時間過大而無法動態及時反應網路環境; (2)壅塞控制演算法無法正確相對應的調整壅塞視窗大小。雖然有些TCP的修改版本已提出解決低吞吐量的方法,但是仍然會有公平性的問題存在,像是TCP Vegas、TCP Westwood等。在本論文我們調整TCP Vegas壅塞視窗的預設門檻值α=1與β=3,更改α與β設為相同數值3,以及在長距離的資料傳輸調整適當的壅塞視窗上限(window size),可達到長距離的多連線共用頻寬的最佳TCP公平性。我們所用的控制機制是探測往返延遲時間來固定住壅塞視窗上限值,以抑制多連線的頻寬競爭,在實驗最後,我們驗證如何去調整TCP Vegas的參數值,可以提升均分與比例分配的公平性。
Nowadays, the fairness issue is one of the most common questions concerned by various TCP congestion control algorithms. The problem of unfair bandwidth-sharing in other discussion of thesis [1, 2], had been encountered in famous TCP version, such as TCP Tahoe and TCP Reno, on long-distance networks.In particular, those long-distance connections through Wide-Area_Network (WAN) suffer from low-throughput and low banwidth-utilization incomparison with short-distance connections. The factors affecting long-distance TCP connections are (1) RTT of long-distance TCP connection is too large to reflect the network dynamics in time; (2) the congestion control algorithm is not able to correctly adjust congestion window size accordingly. Though there were some modified TCP versions proposed to solve the low-throughput, the fairnees issue is remaine as well, such as TCP Vegas, TCP westwood and so on. In the thesis, we adjusts default threshold value α=1 and β=3 of Congestion window on TCP Vegas and set α and β as the same number value 3. Moreover, we adjust proper upper bound of window size in the long distance transmission and many connections in order to optimize the fairness of TCP with long distance bandwidth.Our control algorithms is probe variation of RTT to fixed the upper bound of window size rate for suppress the bandwidth competition in many connections.In the conclusion, we verify how to adjust the parameter value of TCP Vegas can be improvement for average and proportional distribution fairness.
Appears in Collections:[資訊工程系(所) ] 博碩士論文

Files in This Item:

File Description SizeFormat
TCP Vegas於長距離網路傳輸公平性之研究__臺灣博碩士論文知識加值系統.htm國圖100KbHTML906View/Open


All items in STUAIR are protected by copyright, with all rights reserved.

 


無標題文件

著作權政策宣告:

1.

本網站之數位內容為樹德科技大學所收錄之機構典藏,無償提供學術研究與公眾教育等公益性使用,惟仍請適度,合理使用本網站之內容,以尊重著作權人之權益。商業上之利用,則請先取得著作權人之授權。
 
2. 本網站之製作,已盡力防止侵害著作權人之權益,如仍發現本網站之數位內容有侵害著作權人權益情事者,請權利人通知本校護人員(clairhsu@stu.edu.tw),維護人員將立即採取移除該數位著作等補救措施。
 
DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - Feedback