在移动直播场景中,多路径传输控制协议(Multi-Path Transmission Control Protocol,MPTCP)采用的默认调度策略是最小往返时延(Round-Trip Time,RTT)调度(MinRTT),仅依据最小RTT来选择传输路径。这一特性使得安全可靠的专网路径因时延略...在移动直播场景中,多路径传输控制协议(Multi-Path Transmission Control Protocol,MPTCP)采用的默认调度策略是最小往返时延(Round-Trip Time,RTT)调度(MinRTT),仅依据最小RTT来选择传输路径。这一特性使得安全可靠的专网路径因时延略高无法充分利用,且专网与公网切换不及时,容易引发画面卡顿问题。对此,提出一种基于MinRTT的专网优先无感切换调度策略。该策略通过优先检测专网的可用性,并利用卡尔曼滤波器对专网的RTT进行预测,从而实现专网优先传输数据和无感切换的效果。实验结果表明,与MinRTT相比,所提策略在移动直播场景中显著提升了传输稳定性。展开更多
多路径并行传输协议(multi-path transfer control protocol,MPTCP)是当前在异构网络中执行垂直切换时采用的重要策略之一,良好的拥塞控制策略可降低异构网络垂直切换过程中的网络吞吐量波动问题。文章基于强化学习的思想,构建了面向MP...多路径并行传输协议(multi-path transfer control protocol,MPTCP)是当前在异构网络中执行垂直切换时采用的重要策略之一,良好的拥塞控制策略可降低异构网络垂直切换过程中的网络吞吐量波动问题。文章基于强化学习的思想,构建了面向MPTCP的拥塞控制策略生成机制,并将其应用到电力物联网异构网络垂直切换。主要贡献是:基于MPTCP构建强化学习环境,将异构网络时变属性作为环境要素,MPTCP的拥塞控制策略作为智能体行为策略。智能体和异构网络仿真环境的通过垂直切换的执行实现交互学习,生成最优的拥塞控制策略;基于改进后的MPTCP拥塞控制策略实现异构网络的垂直切换,优化异构网络的网络切换进程。仿真及实际场景的测试结果显示,所提方法在电力物联网异构网络切换过程中避免了数据断点,有效降低了异构网络切换过程中的吞吐量波动情况。展开更多
由于传统TCP拥塞控制算法直接应用到MPTCP(Multipath Transport Control Protocol)中存在公平性问题,以及不能有效地发挥多路径传输的优势,因而从公平性方面对MPTCP现有拥塞控制算法进行研究。研究发现,现有的MPTCP拥塞控制算法均受到...由于传统TCP拥塞控制算法直接应用到MPTCP(Multipath Transport Control Protocol)中存在公平性问题,以及不能有效地发挥多路径传输的优势,因而从公平性方面对MPTCP现有拥塞控制算法进行研究。研究发现,现有的MPTCP拥塞控制算法均受到相同的回路时间限制。提出一种基于链路延迟的RTT补偿算法(Compensating for RTT mismatch,C-RTT)。该算法通过设置网络带宽占用比参数以及对MPTCP连接的子流设置侵略因子,从而保证瓶颈链路处MPTCP数据流和TCP数据流公平地共享可用带宽。最后通过NS3仿真实验证明,该算法能够有效地补偿链路中因RTT不等引起的公平性问题,并避免链路之间数据的非周期抖动,且保证了多路径传输的优越性。展开更多
基于广域网中使用MPTCP协议进行数据传输时,由于短流的传输数据量小,每条子流的拥塞窗口在其生命周期内保持很小的状态,这使得1个数据包的丢失也可能导致超时现象发生,从而增大数据流的完成时间,为此,提出一种根据MPTCP数据流特性进行MP...基于广域网中使用MPTCP协议进行数据传输时,由于短流的传输数据量小,每条子流的拥塞窗口在其生命周期内保持很小的状态,这使得1个数据包的丢失也可能导致超时现象发生,从而增大数据流的完成时间,为此,提出一种根据MPTCP数据流特性进行MPTCP数据流调度的算法MPTCP-FSFSm(multi-path TCP flow scheduling based on flow size)。首先,MPTCP-FSFS算法根据MPTCP数据流需要发送的数据量将MPTCP数据流分类;然后,发送端根据当前每条路径往返时延进行MPTCP数据流调度:对于短流,选择往返时延最小的若干条路径进行数据流传输;对于长流,使用所有的路径进行数据流传输。研究结果表明:与MPTCP相比,MPTCP-FSFS在保证长流吞吐率的基础上,能够明显降低短流的数据流完成时间,同时提高数据流平均吞吐率。展开更多
Multipath TCP(MPTCP)is the most significant extension of TCP that enables transmission via multiple paths concurrently to improve the resource usage and throughput of long flows.However,due to the concurrent multiple ...Multipath TCP(MPTCP)is the most significant extension of TCP that enables transmission via multiple paths concurrently to improve the resource usage and throughput of long flows.However,due to the concurrent multiple transfer(CMT)in short flow trans-mission,the congestion window(cwnd)of each MPTCP subflow is too small and it may lead to timeout when a single lost packet cannot be recovered through fast retransmission.As a result,MPTCP has even worse performance for short flows compared to regular TCP.In this paper,we take the first step to analyze the main reason why MPTCP has the diminished performance for short flows,and then we propose M PTCP-SF,which dynamically adjusts the number of subflows for each flow.In particular,MP TCP-SF firstly analyzes the distribution characteristics of the web objects to extract two thresholds to be used for classifying each flow.After eceiving each new ACK,M PTCP-SF periodically counts the data being sent based on per-flow and uses the threshold to classify the we blows.Finally,MPTCP-SF dynamically switches path scheduling model for different classification flows.We conduct extensive experiments in NS3 to evaluate its efficiency.Our evaluation proves that MPTCP-SF decreases the completion time of short flows by over 42.64% com-pared to MPTCP,and the throughput achieved by MPTCP-SF in transmitting long flows is about 11.11%higher than that of MPTCP in a WLAN/LTE wireless network.The results successfully validate the improved performance of MPTCP-SF.展开更多
文摘在移动直播场景中,多路径传输控制协议(Multi-Path Transmission Control Protocol,MPTCP)采用的默认调度策略是最小往返时延(Round-Trip Time,RTT)调度(MinRTT),仅依据最小RTT来选择传输路径。这一特性使得安全可靠的专网路径因时延略高无法充分利用,且专网与公网切换不及时,容易引发画面卡顿问题。对此,提出一种基于MinRTT的专网优先无感切换调度策略。该策略通过优先检测专网的可用性,并利用卡尔曼滤波器对专网的RTT进行预测,从而实现专网优先传输数据和无感切换的效果。实验结果表明,与MinRTT相比,所提策略在移动直播场景中显著提升了传输稳定性。
文摘多路径并行传输协议(multi-path transfer control protocol,MPTCP)是当前在异构网络中执行垂直切换时采用的重要策略之一,良好的拥塞控制策略可降低异构网络垂直切换过程中的网络吞吐量波动问题。文章基于强化学习的思想,构建了面向MPTCP的拥塞控制策略生成机制,并将其应用到电力物联网异构网络垂直切换。主要贡献是:基于MPTCP构建强化学习环境,将异构网络时变属性作为环境要素,MPTCP的拥塞控制策略作为智能体行为策略。智能体和异构网络仿真环境的通过垂直切换的执行实现交互学习,生成最优的拥塞控制策略;基于改进后的MPTCP拥塞控制策略实现异构网络的垂直切换,优化异构网络的网络切换进程。仿真及实际场景的测试结果显示,所提方法在电力物联网异构网络切换过程中避免了数据断点,有效降低了异构网络切换过程中的吞吐量波动情况。
文摘由于传统TCP拥塞控制算法直接应用到MPTCP(Multipath Transport Control Protocol)中存在公平性问题,以及不能有效地发挥多路径传输的优势,因而从公平性方面对MPTCP现有拥塞控制算法进行研究。研究发现,现有的MPTCP拥塞控制算法均受到相同的回路时间限制。提出一种基于链路延迟的RTT补偿算法(Compensating for RTT mismatch,C-RTT)。该算法通过设置网络带宽占用比参数以及对MPTCP连接的子流设置侵略因子,从而保证瓶颈链路处MPTCP数据流和TCP数据流公平地共享可用带宽。最后通过NS3仿真实验证明,该算法能够有效地补偿链路中因RTT不等引起的公平性问题,并避免链路之间数据的非周期抖动,且保证了多路径传输的优越性。
文摘基于广域网中使用MPTCP协议进行数据传输时,由于短流的传输数据量小,每条子流的拥塞窗口在其生命周期内保持很小的状态,这使得1个数据包的丢失也可能导致超时现象发生,从而增大数据流的完成时间,为此,提出一种根据MPTCP数据流特性进行MPTCP数据流调度的算法MPTCP-FSFSm(multi-path TCP flow scheduling based on flow size)。首先,MPTCP-FSFS算法根据MPTCP数据流需要发送的数据量将MPTCP数据流分类;然后,发送端根据当前每条路径往返时延进行MPTCP数据流调度:对于短流,选择往返时延最小的若干条路径进行数据流传输;对于长流,使用所有的路径进行数据流传输。研究结果表明:与MPTCP相比,MPTCP-FSFS在保证长流吞吐率的基础上,能够明显降低短流的数据流完成时间,同时提高数据流平均吞吐率。
基金This work is supported by the National Natural Science Foundation of China(No.61602171,61602172)Scientific Research Fund of Hunan Provincial Education Department(No.17C0960,16C0050)Hunan Provincial Natural Science Foundation of China(No.2017JJ2016).
文摘Multipath TCP(MPTCP)is the most significant extension of TCP that enables transmission via multiple paths concurrently to improve the resource usage and throughput of long flows.However,due to the concurrent multiple transfer(CMT)in short flow trans-mission,the congestion window(cwnd)of each MPTCP subflow is too small and it may lead to timeout when a single lost packet cannot be recovered through fast retransmission.As a result,MPTCP has even worse performance for short flows compared to regular TCP.In this paper,we take the first step to analyze the main reason why MPTCP has the diminished performance for short flows,and then we propose M PTCP-SF,which dynamically adjusts the number of subflows for each flow.In particular,MP TCP-SF firstly analyzes the distribution characteristics of the web objects to extract two thresholds to be used for classifying each flow.After eceiving each new ACK,M PTCP-SF periodically counts the data being sent based on per-flow and uses the threshold to classify the we blows.Finally,MPTCP-SF dynamically switches path scheduling model for different classification flows.We conduct extensive experiments in NS3 to evaluate its efficiency.Our evaluation proves that MPTCP-SF decreases the completion time of short flows by over 42.64% com-pared to MPTCP,and the throughput achieved by MPTCP-SF in transmitting long flows is about 11.11%higher than that of MPTCP in a WLAN/LTE wireless network.The results successfully validate the improved performance of MPTCP-SF.
