發(fā)布時(shí)間：2018-01-09 21:49

  本文關(guān)鍵詞：移動(dòng)網(wǎng)絡(luò)中TCP數(shù)據(jù)重傳時(shí)間優(yōu)化研究　出處：《廣西大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： TCP RTO 移動(dòng)網(wǎng)絡(luò) RRC 偽超時(shí)重傳

【摘要】：近年來隨著通信技術(shù)的進(jìn)步以及移動(dòng)設(shè)備的普及,移動(dòng)網(wǎng)絡(luò)成為當(dāng)今世界發(fā)展最快、市場(chǎng)潛力最大、前景最誘人的業(yè)務(wù)之一。TCP流作為移動(dòng)網(wǎng)絡(luò)中承載絕大多數(shù)任務(wù)的傳輸協(xié)議,它的性能將決定移動(dòng)網(wǎng)絡(luò)能否提供高質(zhì)量的通訊服務(wù)。然而,TCP在移動(dòng)網(wǎng)絡(luò)中會(huì)發(fā)生過多的偽超時(shí)重傳。這是因?yàn)樵谝苿?dòng)網(wǎng)絡(luò)中由于無線資源控制(RRC)會(huì)在不同的狀態(tài)轉(zhuǎn)換,這些轉(zhuǎn)換導(dǎo)致TCP包經(jīng)歷巨大的突發(fā)延時(shí)從而發(fā)生超時(shí)重傳因此降低了TCP的性能。本文集中討論了移動(dòng)網(wǎng)絡(luò)中TCP重傳時(shí)間存在的問題,以期待為改善移動(dòng)網(wǎng)絡(luò)中的TCP性能提供優(yōu)化策略。在有線網(wǎng)絡(luò)中TCP使用重傳時(shí)間來保證數(shù)據(jù)包的可靠傳輸,但由于移動(dòng)網(wǎng)絡(luò)中RRC轉(zhuǎn)換的特性,使得基于有線網(wǎng)絡(luò)設(shè)計(jì)的重傳機(jī)制無法很好的適應(yīng)移動(dòng)網(wǎng)絡(luò)。針對(duì)這些問題,下面是本文的主要研究工作：(1)介紹了TCP重傳時(shí)間以及移動(dòng)網(wǎng)絡(luò)中RRC的相關(guān)知識(shí),闡明了由于RRC狀態(tài)轉(zhuǎn)換導(dǎo)致的TCP偽超時(shí)重傳是TCP對(duì)擁塞狀態(tài)錯(cuò)誤的判斷。(2)分析并驗(yàn)證了這種偽超時(shí)重傳對(duì)TCP協(xié)議性能的影響。偽超時(shí)重傳對(duì)TCP性能的影響主要包括：降低TCP流的有效吞吐率以及增加TCP傳輸?shù)难訒r(shí)。通過真實(shí)環(huán)境中的測(cè)試,驗(yàn)證了該偽超時(shí)重傳直接產(chǎn)生多余的TCP重傳包降低了有效吞吐率,以及在重傳后擁塞窗口和慢啟動(dòng)閥門值降低、RTO值偏離正常值間接導(dǎo)致TCP傳輸延時(shí)的增加。(3)提出了對(duì)重傳時(shí)間的優(yōu)化策略。本文優(yōu)化策略通過調(diào)整RTO值來避免偽超時(shí)重傳,并在Linux內(nèi)核中實(shí)現(xiàn)。在商用3G網(wǎng)絡(luò)中本文進(jìn)行了對(duì)比測(cè)試,結(jié)果表明該優(yōu)化策略不僅減少了TCP連接的流量和完成時(shí)間、使得RTO值保持正常并且降低了TCP的重傳率。最后,給出本文的總結(jié),并就下一步研究給出方向,為在以后的工作中繼續(xù)深入研究做好準(zhǔn)備。
[Abstract]:In recent years, with the development of communication technology and the popularity of mobile devices, mobile network has become the world's fastest growing market potential. TCP flow as a transport protocol that carries most tasks in mobile networks, its performance will determine whether the mobile network can provide high-quality communication services. Too many pseudo-timeout retransmissions occur in the mobile network because the RRCs are converted in different states because of the wireless resource control in the mobile network. These transformations cause TCP packets to undergo a huge burst delay and thus cause time-out retransmission, which reduces the performance of TCP. This paper focuses on the problem of TCP retransmission time in mobile networks. In order to improve the performance of TCP in mobile networks, TCP uses retransmission time to ensure the reliable transmission of data packets, but due to the characteristics of RRC conversion in mobile networks. The retransmission mechanism based on wired network design can not adapt to the mobile network very well. The following is the main research work of this paper: 1) introduce the TCP retransmission time and the related knowledge of RRC in mobile network. This paper illustrates that the TCP pseudo-timeout retransmission caused by RRC state transition is the judgment of congestion state error by TCP. The effect of pseudo-timeout retransmission on TCP performance is analyzed and verified. The effects of pseudo-timeout retransmission on TCP performance are as follows:. Reduce the effective throughput of TCP stream and increase the delay of TCP transmission. Pass the test in real environment. It is verified that the pseudo-timeout retransmission directly produces redundant TCP retransmission packets which reduce the effective throughput and the value of congestion window and slow start valve after retransmission. The RTO value deviation indirectly leads to the increase of TCP transmission delay.) an optimization strategy for retransmission time is proposed. This optimization strategy avoids pseudo-timeout retransmission by adjusting the RTO value. The results show that the optimization strategy not only reduces the traffic and completion time of TCP connection. The RTO value is kept normal and the retransmission rate of TCP is reduced. Finally, the summary of this paper is given, and the direction of further research is given in order to prepare for further research in the future.
【學(xué)位授予單位】：廣西大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN929.5

【共引文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 袁國(guó)良;車聯(lián)網(wǎng)終端設(shè)備的關(guān)鍵技術(shù)研究[D];大連海事大學(xué);2013年

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本文編號(hào)：1402609