異質網路下軟體定義網路輔助之MPTCP路徑排程機制

SDN-assisted MPTCP Path Scheduling for Heterogeneous Networks

鄭淳丰(Chun-Feng Zheng)

指導教授 ： 王國禎

國立交通大學/資訊學院/資訊科學與工程研究所/碩士(2019年)

摘要

在異質網路下，MPTCP的流通量會顯著的降低。現有的研究項目使用主機上的網路資訊如來回通訊延遲(RTT)與壅塞視窗大小(CWND)去預測網路狀態以做出排程。代表性之研究Earliest Completion First (ECF) 排程使用RTT與CWND預測封包在快速與慢速路徑的傳輸時間。然而，當面對大象流，兩路徑的RTT差距增加時，ECF會因所預測的傳輸時間之增加導致慢速路徑的利用率下降。除此之外，只使用主機上的網路資訊來推測網路狀態無法快速地反應網路環境的變化。為了處理這些問題，我們提出異質網路下軟體定義網路輔助之MPTCP路徑排程機制(SMPS)。藉由使用SDN控制器監測全域網路環境，SMPS可以即時對網路環境的變化做出反應，以充分利用所有路徑來提升總流通量。我們將SMPS與ECF及預設的排程演算法(minRTT)比較。實驗結果顯示在快速與慢速路徑延遲差距大於30ms時，SMPS的總流通量比ECF高11%，且其平均檔案下載時間比ECF短14%。

關鍵字

異質網路 ； 軟體定義網路 ； 路徑排程 ； 多路徑TCP

並列摘要

The throughput of MPTCP (MultiPath TCP) suffers a lot when network paths are heterogeneous. Existing works use host network information like RTT (Round-Trip Time) and CWND (Congestion Window) to predict network status. A representative work, ECF (Earliest Completion First), uses RTT and CWND to estimate the transmission times on the fast path and the slow path. However, for an elephant flow, when the difference of the two RTTs increases, ECF will underuse the slow path due to the inflation of the estimated transmission time. In addition, only using host network information cannot rapidly react to network fluctuations. To deal with this problem, we propose an SDN-assisted MPTCP path scheduling for heterogeneous networks (SMPS). By using an SDN (Software-Defined Networking) controller to monitor global network information, the proposed SMPS can rapidly react to network fluctuations and fully utilize all paths to improve total throughput. We compare SMPS with ECF and the default scheduler (minRTT). Experiment results have shown that the total throughput of SMPS is 11% higher than ECF and the average file download time of SMPS is 14% shorter than ECF when the difference of the delay of the fast and slow paths is larger than 30ms.

並列關鍵字

Heterogeneous network ； MPTCP ； path scheduling ； software-defined networking

參考文獻

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