網際網路服務之智慧傳輸策略

隨著無線通訊技術的演進，多媒體與雲端運算在新世代網際網路中逐漸成為最受歡迎的通訊服務。不論電腦或者是行動裝置，大多都已至少配備著兩個以上的有線或是無線的網路接取介面。因此學者們提出了Stream Control Transmission Protocol (SCTP) 以有效使用所有網路接取介面來增進傳輸效能及可靠性，而CMT-SCTP的發表更將SCTP擴展至支援多重路徑同時傳輸，充份利用頻寬提昇系統效能。由於SCTP的壅塞控制機制是承襲TCP而來的，如同TCP所遭遇到的問題，SCTP在有線與無線結合之異質性網路中仍會遭受到非必要的效能減損。此乃因為SCTP的壅塞控制機制無法判別封包遺失的原因，以至於不恰當的調降壅塞窗口。為了解決上述問題來提昇效能，我們提出一個應用於異質性網路中以延遲變異為基礎、擁有點對點特性的壅塞控制機制來增進效能，並提出以延遲變異為基礎的封包遺失判別方針，使整體方法更加強健。此外還整合了可利用頻寬的預測機制，穩定傳輸時的瓶頸流量，實驗結果顯示出我們提出的方法在異質性網路與多重路徑同時傳輸的環境下，確實有效地使效能顯著的提昇。

關鍵字

多重路徑同時傳輸；延遲變異；壅塞控制

並列摘要

With the advances of wireless communication technologies, it significantly enables multimedia and cloud-related applications for the new generation Internet services. Indeed, most of mobile devices are equipped with multiple wired or wireless network interfaces. Stream Control Transmission Protocol (SCTP) has been proposed for effectively utilizing all network interfaces to improve performance and reliability. Moreover, Concurrent Multipath Transfer (CMT) is an extension of SCTP to support concurrent data transmission through multiple available paths. However, SCTP suffers performance degradation over wired-wireless heterogeneous networks since its congestion control mechanism is only slightly modified from traditional TCP. Because SCTP cannot differentiate loss events between wireless and congestion, which makes the congestion window size be reduced inappropriately. In this thesis, we propose a jitter-based congestion control scheme with end-to-end semantics over wired-wireless networks to address the above problem. Besides, we also solved ineffective jitter ratio problem that may misjudge congestion loss event. Available bandwidth estimation scheme is further integrated into our congestion control mechanism to make the bottleneck more stabilized. Simulation results reveal that proposed schemes give prominence to improve performance effectively over wired-wireless networks.

並列關鍵字

SCTP ； Concurrent multipath transfer ； Jitter-based congestion control

參考文獻

[1] Q. Bi, G. I. Zysman, and H. Xu, “Wireless mobile communications at the start of the 21st century,” IEEE Communications Magazine, vol. 39, no. 1, pp. 110–116, 2001.

[2] A. Greenspan, M. Klerer, J. Tomcik, R. Canchi, and J. Wilson, “IEEE 802.20: Mobile broadband wireless access for the twenty-first century,” IEEE Communications Magazine, vol. 46, no. 7, pp. 56–63, 2008.

[3] K. C. Leung and V. O. K. Li, “Transmission Control Protocol (TCP) in wireless networks: issues, approaches and challenges,” IEEE Communications Surveys, vol. 4, no. 4, pp. 64–79, 2006.

[4] R. Stewart and C. Metz, “SCTP: new transport protocol for TCP/IP,” IEEE Internet Computing, vol. 5, no. 6, pp. 64–69, 2001.

[9] S. Fu and M. Atiquzzaman, “SCTP: state of the art in research products, and technical challenges,” IEEE Communications Magazine, vol. 42, no. 4, pp. 64–76, 2004.

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網際網路服務之智慧傳輸策略

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