系統識別號 | U0002-2407201416554400 |
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DOI | 10.6846/TKU.2014.00985 |
論文名稱(中文) | FHR-SCTP : 適應性SCTP壅塞控制機制提升換手效率之研究 |
論文名稱(英文) | FHR-SCTP : The Research of A Quality Aware SCTP Congestion Control Mechanism to Improve Handover Efficiency |
第三語言論文名稱 | |
校院名稱 | 淡江大學 |
系所名稱(中文) | 電機工程學系碩士班 |
系所名稱(英文) | Department of Electrical and Computer Engineering |
外國學位學校名稱 | |
外國學位學院名稱 | |
外國學位研究所名稱 | |
學年度 | 102 |
學期 | 2 |
出版年 | 103 |
研究生(中文) | 張辰瑋 |
研究生(英文) | Chen-Wei Chang |
學號 | 602450016 |
學位類別 | 碩士 |
語言別 | 繁體中文 |
第二語言別 | |
口試日期 | 2014-07-07 |
論文頁數 | 52頁 |
口試委員 |
指導教授
-
李維聰
委員 - 朱國志 委員 - 吳庭育 |
關鍵字(中) |
串流控制傳輸協定 換手 多重位址 壅塞視窗 壅塞控制 |
關鍵字(英) |
SCTP handover Multi-homing congestion windows congestion control |
第三語言關鍵字 | |
學科別分類 | |
中文摘要 |
在高科技的社會中,隨著網路的興起、智慧型行動裝置的成熟及頻寬不斷的提升,讓現代的生活越來越便利。但因為人們過度集中於都市或移動速度過快原因,造成了頻寬的爭奪及網路換手的問題,如何解決目前正都在被廣泛的議論當中。 Stream Control Transmission Protocol(SCTP),在2000年由IETF所提出,RFC 4960詳細地定義了SCTP。SCTP是屬於OSI網路七層架構中的傳輸層,SCTP結合TCP及UDP的優點,是一種點對點的傳輸,兼具可靠性服務的通訊協定。SCTP最為顯著特色的為多重串流(Multi-stream)與多重位址(Multi-homing)的特性。 其中,多重位址能同時擁有多組IP,並建立多條異質或同質的網路連線,也因為這特性,SCTP是適合來應用在軟式換手(soft-handover)的流程中。在原協定中所訂定的壅塞控制機制中,在換手時,新路徑的壅塞視窗(Congestion Window, CWND)因為沒有資料在傳輸,以致於CWND都處於接近初始值的數值。因此,在換手後會因為CWND的急遽下降,造成傳輸速率也瞬間急遽下降,使在換手後無法保持原有的傳輸效率。 本論文提出Fast Handover Recover - SCTP(FHR-SCTP)新的機制,基於SCTP Efficient Flow Control During Handover (SCTP-EFC)做更進階的改善。在換手後,新路徑除了繼承舊路徑的CWND外,並將其設定以慢啟動(Slow-Start)的方式來快速地到達新路徑CWND的峰值。除了保持原有的傳輸效率外,使新路徑能立即的擁有最大的傳輸量。若換手至較差通道品質的網路環境時,可能因為過大的CWND造成傳輸量過大,而導致封包掉落,因此若在換手後偵測到封包遺失時,將過大的CWND扣除遺失封包的大小,使新路徑能以可接受的最大傳輸量繼續傳輸。 本論文的實驗中,在換手後CWND遞增至最高值所花時間的部分,與SCTP及SCTP-EFC相比,提升了0%~42.5%;當FHR-SCTP換手機制在換手後CWND到達峰值時,比SCTP及SCTP-EFC多傳送0%~41.72%的資料量,由此來驗證,FHR-SCTP有較好的換手效率。 |
英文摘要 |
In the high-tech society, the technique of network and the mobile devices have become mature nowadays. All user usually surf the internet on the mobile device with mobile network, but all the base station have limit service range. Therefore, handover occurs all the time in our life. How to surf the internet with high efficiency during handover is a big issue. SCTP was accepted by IETF in 2000, and SCTP included in the standard of RFC4960.SCTP, TCP and UDP are a transport protocol in OSI network structure. SCTP has advantages of TCP and UDP. The outstanding feature of SCTP is Multi-stream and Multi-homing. Multi-homing that the devices could contain two or more networking interface is suit to implement soft-handover. However, there are still some negative effects by congestion control mechanism of SCTP during handover, the transmission rate will greatly decline during handover. This paper presents a Fast Handover Recover - SCTP (FHR-SCTP) mechanism. It improves the mechanism that is presented by the paper of SCTP Efficient Flow Control During Handover (SCTP-EFC), and it can fast recover the CWND after handover. Besides inheriting the CWND of the old primary path to the new primary path, it sets the ssthresh of the new primary path to initial value after handover. It make the CWND of the new primary path increase by slow-start phase and quickly own maximum transmission traffic. Last, if FHR-SCTP handover to poor quality path, maybe the CWND is too large for the new primary path and makes the new primary path cannot afford the traffic volume. So, we store the TSN (Transmission sequence number) to calculate the dropped packet size before handover. If it occurs packet losing at first time after handover, we should decrease the CWND by the dropped packet size. The result shows that FHR-SCTP is more efficient than SCTP and SCTP-EFC .FHR-SCTP improves the time of reaching the max CWND about 0.83% to 42.5% with other mechanisms after handover, and when the CWND of FHR-SCTP reaches the max CWND after handover, FHR-SCTP transmits more than 0%~41.72% packet size with SCTP and SCTP-EFC. |
第三語言摘要 | |
論文目次 |
第一章 緒論 1 1.1 前言 1 1.2 動機與目的 2 1.3 論文章節架構 4 第二章 背景知識與相關文獻 5 2.1 換手(Handover) 5 2.2 串流控制傳輸協定(Stream Control Transmission Protocol,SCTP) 8 2.2.1 簡介 8 2.2.2 多重串流(Multi-stream) 9 2.2.3 多重位址(Multi-homing) 9 2.2.4 連線及斷線機制 10 2.2.5 區塊綁定(Chunk Bundling)與分割(Chunk Fragmentation)機制 12 2.2.6 選擇性回應(Selective acknowledge,SACK)機制 14 2.2.7 路徑監測(Heartbeat)機制 15 2.2.8 SCTP、TCP與UDP的特性比較 15 2.3 壅塞控制(Congestion control)機制 16 2.3.1 壅塞視窗(Congestion Window,CWND) 16 2.3.2 慢啟動臨界值(Slow-Start Threshold, ssthresh) 17 2.3.3 慢啟動機制(Slow-Start phase) 17 2.3.4 壅塞避免機制(Congestion Avoidance phase) 17 2.3.5 封包遺失機制 18 2.3.6 快速重傳機制 18 2.3.7 重傳計時器逾時機制(T3-rtx timer expires) 18 2.4 傳統SCTP應用在換手的流程 19 2.5 相關文獻探討 21 2.5.1 SCTP Efficient Flow Control(SCTP-EFC) 21 第三章 適應性SCTP壅塞控制機制 22 3.1 Fast Handover Recover - SCTP(FHR-SCTP) 22 第四章 模擬結果與效能分析 26 4.1 模擬環境 26 4.2 模擬情境 27 4.3 模擬結果 28 4.4 效能分析 40 4.4.1 在較高CWND發生換手的效能分析 41 4.4.2 在較低CWND發生換手的效能分析 44 第五章 結論與未來展望 49 參考文獻 51 圖目錄 圖2.1 軟式換手流程圖 7 圖2.2 SCTP傳輸架構圖 [1] 8 圖2.3 多重串流架構圖 9 圖2.4 多重位址架構圖 10 圖2.5 SCTP連線及斷線流程 11 圖2.6 SCTP封包格式 12 圖2.7 SCTP資料區塊格式 13 圖2.8 SCTP SACK區塊格式 14 圖2.9 壅塞控制參數變化量 16 圖2.10 傳統SCTP換手流程圖 19 圖2.11 傳統SCTP換手時CWND變化圖 20 圖3.1 FHR-SCTP換手流程圖 25 圖4.1模擬環境架構圖 27 圖4.2情境一於30秒發生換手模擬─CWND變化量 29 圖4.3情境二於30秒發生換手模擬─CWND變化量 30 圖4.4情境三於30秒發生換手模擬─CWND變化量 31 圖4.5情境四於30秒發生換手模擬─CWND變化量 32 圖4.6情境五於30秒發生換手模擬─CWND變化量 33 圖4.7情境一於40秒發生換手模擬─CWND變化量 35 圖4.8情境二於40秒發生換手模擬─CWND變化量 36 圖4.9情境三於40秒發生換手模擬─CWND變化量 37 圖4.10情境四於40秒發生換手模擬─CWND變化量 38 圖4.11情境五於40秒發生換手模擬─CWND變化量 39 圖4.12於30秒換手CWND到達峰值所花的時間 41 圖4.13於30秒換手FHR-SCTP對其他機制CWND達峰值所提升的效率 42 圖4.14於30秒換手FHR-SCTP中CWND到達峰值的TSN 43 圖4.15於30秒換手FHR-SCTP中CWND到達峰值時的TSN對其他機制TSN所提升的效率 44 圖4.16於40秒換手CWND到達峰值所花的時間 45 圖4.17於40秒換手FHR-SCTP對其他機制CWND達峰值所提升的效率 46 圖4.18於40秒換手FHR-SCTP中CWND到達峰值的TSN 47 圖4.19於40秒換手FHR-SCTP中CWND到達峰值時的TSN對其他機制TSN所提升的效率 48 表目錄 表 2.1 換手方式差異性說明 6 表 2.2 軟式換手步驟說明 6 表 2.3 SCTP、TCP及UDP特性比較圖 15 表 4.1 模擬情境 28 表 4.2情境一於30秒發生換手模擬─花費時間及TSN紀錄 29 表 4.3情境二於30秒發生換手模擬─花費時間及TSN紀錄 30 表 4.4情境三於30秒發生換手模擬─花費時間及TSN紀錄 31 表 4.5情境四於30秒發生換手模擬─花費時間及TSN紀錄 32 表 4.6情境五於30秒發生換手模擬─花費時間及TSN紀錄 33 表 4.7情境一於40秒發生換手模擬─花費時間及TSN紀錄 35 表 4.8情境二於40秒發生換手模擬─花費時間及TSN紀錄 36 表 4.9情境三於40秒發生換手模擬─花費時間及TSN紀錄 37 表 4.10情境四於40秒發生換手模擬─花費時間及TSN紀錄 38 表 4.11情境五於40秒發生換手模擬─花費時間及TSN紀錄 39 |
參考文獻 |
[1] R. Stewart, “Stream control transmission protocol”, RFC 4960, September 2007. [2] Keun Jae Lee, Sang Su Nam, and Byung In Mun, “SCTP Efficient Flow Control During Handover”, IEEE WCNC 2006, April 2006. [3] R. Stewart, Q. Xie, K. Morneault, C. Sharp, H. Schwarzbauer, T. Taylor,I. Rytina, M. Kalla, L. Zhang, and V. Paxson, “Stream control transmission protocol”, RFC 2960, October 2000. [4] Allman, M., Paxson, V. and W. Stevens, “TCP Congestion Control”, RFC 2581, April 1999. [5] ns-2 network simulator(ver. 2). LBL, URL:http://www.isi.edu/nsnam/ns [6] R. Stewart, M. Ramalho, Q. Xie, M. Tuexen, and P. Conrad, “Stream Control Transmission Protocol(SCTP)Dynamic Address Reconfiguration”, draft-ietf-tsvwg-addip-sctp-13(work in progress),November 2005. [7] Kun Zheng, Min Liu, Zhong-Cheng Li and Gang Xu, “SHOP: An Integrated Scheme for SCTP Handover Optimization in Multihomed Environments”, IEEE GLOBECOM 2008, December 2008. [8] Chin-Shiuh Shieh, I-Cheng Lin, and Wei Kuang Lai, “Improvement of SCTP Performance in Vertical Handover”, IEEE ISDA '08, November 2008. [9] Dong Phil Kim, Jong Shik Ha, Sang Tae Kim, and Seok Joo Koh, “Use of SCTP for IP Handover Support”, IEEE Fourth Annual ACIS International Conference, 2005. [10] Preethi Natarajan, Fred Baker, Paul D. Amer and Jonathan T. Leighton, “SCTP: What, Why, and How”, IEEE Internet Computing (Volume:13 , Issue: 5 ), Sept.-Oct. 2009. [11] Sinh Chung Nguyen, Thi Mai Trang Nguyen and Guy Pujolle, “Performance Improvements of Mobile SCTP during handover period”, ICWMC 2011, June 19-24, 2011. [12] Shaojian Fu and Mohammed Atiquzzaman, “SCTP: State of the Art in Research, Products, and Technical Challenges”, IEEE Communications Magazine (Volume:42 , Issue: 4 ), Apr 2004. [13] Thomas Dreibholz, Erwin P. Rathgeb, Irene Rüngeler, Robin Seggelmann, Michael Tüxen and Randall R. Stewart, “Stream control transmission protocol: Past, current, and future standardization activities”, IEEE Communications Magazine (Volume:49 , Issue: 4), April 2011. [14] Koh, S., et al., "mSCTP for Soft Handover in Transport Layer", IEEE Communications Letters, Vol. 8, No. 3, pp.189 - 191, March 2004. [15] Janardhan R. Iyengar , O L. Caro , Paul D. Amer , Gerard J. Heinz and Randall R. Stewart, “Making SCTP More Robust to Changeover”, SPECTS 2003, July 2003. [16] R. Stewart et al., “Sockets API Extensions for Stream Control Transmission Protocol (SCTP)”, IETF Internet draft, work in progress, Feb. 2009. [17] R. Stewart, et al., “Stream Control Transmission Protocol Partial Reliability Extension,”IETF RFC 3758, May 2004. [18] R. Stewart, et al., “Socket API Extensions for Stream Control Transmission Protocol,”IETF Internet Draft, June 2006. [19] 吳勇霆, 李維聰, 張恆耀, “修改SCTP 壅塞控制以提升換手效率”, National Symposium on Telecommunications 2013, November 2013. |
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