共查询到19条相似文献,搜索用时 187 毫秒
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针对分层多播接收者的可用带宽异构性问题,提出了一种自适应动态分层多播拥塞控制算法(ADLM).ADLM自适应地运用最优层输率分配算法来满足接收者的异构性,ADLM可以根据网络情况变化动态地调整分层的数量以及每一分层的层速率.仿真实验表明,该拥塞控制策略比分层组播控制常用的典型策略(RLC)更有效地利用网络带宽,解决网络带宽的异构性问题,同时ADLM是TCP友好的,较好地改进了分层多播拥塞控制的性能. 相似文献
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分层组播是解决组播通信当中底层网络结构异构性,适应网络动态变化的一种最佳解决方案。本论文分析了现有的分层组播技术,介绍了采用主动网进行接收方驱动的分层组播的新方案(RLM-AN)。不同于大多数的分层组播方法的端到端的拥塞控制机制,RLM-AN是分布式的TCP友好的拥塞控制机制。方案中把组播树看成是一组虚拟链路,在每个虚拟链路上进行TCP友好的拥塞控制。通过在网络内部的主动节点处进行拥塞控制,传输系统可以得到更为平滑的和更为TCP友好的吞吐量,以及对网络内部拥塞的快速响应。同时,本论文对RLM-AN在技术细节实现上的若干问题进行了讨论。 相似文献
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分层组播是解决组播通信当中底层网络结构异构性,适应网络动态变化的一种最佳解决方案。本论分析了现有的分层组播技术,介绍了采用主动网进行接收方驱动的分层组播的新方案(RLM-AN)。不同于大多数的分层组播方法的端到端的拥塞控制机制,RLM-AN是分布式的TCP友好的拥塞控制机制。方案中把组播树看成是一组虚拟链路,在每个虚拟链路上进行TCP友好的拥塞控制。通过在网络内部的主动节点处进行拥塞控制,传输系统可以得到更为平滑的和更为TCP友好的吞吐量,以及对网络内部拥塞的快速响应。同时,本论对RLM-AN在技术细节实现上的若干问题进行了讨论。 相似文献
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针对GEO卫星网络带宽时延积较大、拥塞控制机制不完善的问题,提出了一种面向GEO卫星网络的多速率多播拥塞控制机制MMCCM_GEO.首先,在保证接收端请求速率最大化的前提下,将GEO卫星网络中的多速率多播问题转化为非线性优化问题,并采用改进的模拟退火算法对其求解,得到了最优的接收端请求速率.其次,通过采用代理节点实现反馈信息的汇集与丢失数据的恢复,有效地解决了反馈内暴及数据恢复问题.仿真结果表明,与目前GEO卫星网络中典型的多速率多播拥塞控制机制相比,本文的拥塞控制机制有效地提高了数据吞吐量和带宽利用率,降低了GEO卫星网络中的数据传输时延,同时也具备了更好的可扩展性. 相似文献
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一种在接收端实现的TCP-Friendly拥塞控制机制 总被引:9,自引:0,他引:9
本文提出了一种基于速率的单播TCP-Friendly拥塞控制算法——RAAR(Rate Adaptation at Receivers)控制机制.RAAR是一种接收端的速率自适应算法,它抛弃了每包反馈机制,采用GAIMD(General Additive Increase Multiplicative Decrease)策略进行拥塞控制,其主要控制操作由接收方完成.本文建立了简化的数学模型对其进行吞吐量的分析,得到在RAAR中用于TCP-Friendly 的GAIMD拥塞控制中α与 β的关系.通过与TFRC及TEAR这两种重要的TCP-Friendly协议进行对比研究发现,RAAR协议在对TCP协议的友好性,协议内的公平性以及速率的平滑性等方面具有更好的综合性能.由于RAAR不需进行每包反馈,且主要功能在接收方实现,因此可方便地将该机制引入多媒体组播传输系统中. 相似文献
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In this paper, we develop, analyze and implement a congestion control scheme in a noncooperative game framework, where each user's cost function is composed of a pricing function proportional to the queueing delay experienced by the user, and a fairly general utility function which captures the user demand for bandwidth. Using a network model based on fluid approximations and through a realistic modeling of queues, we establish the existence of a unique equilibrium as well as its global asymptotic stability for a general network topology, where boundary effects are also taken into account. We also provide sufficient conditions for system stability when there is a bottleneck link shared by multiple users experiencing nonnegligible communication delays. In addition, we study an adaptive pricing scheme using hybrid systems concepts. Based on these theoretical foundations, we implement a window-based, end-to-end congestion control scheme, and simulate it in ns-2 network simulator on various network topologies with sizable propagation delays. 相似文献
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基于显式速率的TCP友好的UDP拥塞控制策略 总被引:2,自引:0,他引:2
本文提出了一种基于显式速率的UDP拥塞控制策略:通过源端和网络中的路由器相互配合,使得实时UDP应用能够根据网络的反馈以瓶颈链路的公平带宽为速率发送数据。此种控制策略对TCP应用是友好的,并且提高了网络的吞吐量和利用率。仿真结果表明:基于显式速率的UDP拥塞控制策略与采用TFRC(TCP—Friendly Rate Control)的UDP拥塞控制策略相比,在吞吐量、TCP友好性等方面性能有较大提高。 相似文献
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The conventional TCP tends to suffer from performance degradation due to packet corruptions in the wireless lossy channels, since any corruption event is regarded as an indication of network congestion. This paper proposes a TCP error and congestion control scheme using corruption‐aware adaptive increase and adaptive decrease algorithm to improve TCP performance over wireless networks. In the proposed scheme, the available network bandwidth is estimated based on the amount of the received integral data as well as the received corrupted data. The slow start threshold is updated only when a lost but not corrupted segment is detected by sender, since the corrupted packets still arrive at the TCP receiver. In the proposed scheme, the duplicated ACKs are processed differently by sender depending on whether there are any lost but not corrupted segments at present. Simulation results show that the proposed scheme could significantly improve TCP throughput over the heterogeneous wired and wireless networks with a high bit error rate, compared with the existing TCP and its variants. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Yiwei Thomas Hou Shivendra S. Panwar Zhi‐Li Zhang Henry Tzeng Ya‐Qin Zhang 《International Journal of Communication Systems》2000,13(2):117-143
While existing research shows that feedback‐based congestion control mechanisms are capable of providing better video quality and higher link utilization for rate‐adaptive packet video, there has been relatively little study on how to share network bandwidth among competing rate‐adaptive video connections, when feedback control is used in a fully distributed network. This paper addresses this issue by presenting a framework of network bandwidth sharing for transporting rate‐adaptive packet video using feedback. We show how a weight‐based bandwidth sharing policy can be used to allocate network bandwidth among competing video connections and design a feedback control algorithm using an Available Bit Rate (ABR)‐like flow control mechanism. A novel video source rate adaptation algorithm is also introduced to decouple a video source's actual transmission rate from the rate used for distributed protocol convergence. Our feedback control algorithm provides guaranteed convergence and smooth source rate adaptation to our weight‐based bandwidth sharing policy under any network configuration and any set of link distances. Finally, we show the on‐line minimum rate renegotiation and weight adjustment options in our feedback control algorithm, which offer further flexibility in network bandwidth sharing for video connections. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
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Xiaohui Li Junfeng Wang Li Han Yingjie Zhou Sunyoung Han 《Wireless Communications and Mobile Computing》2016,16(17):3056-3069
As the exponential growth of the Internet, there is an increasing need to provide different types of services for numerous applications. Among these services, low‐priority data transfer across wide area network has attracted much attention and has been used in a number of applications, such as data backup and system updating. Although the design of low‐priority data transfer has been investigated adequately in low speed networks at transport layer, it becomes more challenging for the design of low‐priority data transfer with the adaptation to high bandwidth delay product networks than the previous ones. This paper proposes an adaptive low‐priority protocol to achieve high utilization and fair sharing of links in high bandwidth delay product networks, which is implemented at transport layer with an end‐to‐end approach. The designed protocol implements an adaptive congestion control mechanism to adjust the congestion window size by appropriate amount of spare bandwidth. The improved congestion mechanism is intent to make as much use of the available bandwidth without disturbing the regular transfer as possible. Experiments demonstrate that the adaptive low‐priority protocol achieve efficient and fair bandwidth utilization, and remain non‐intrusive to high priority traffic. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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The use of enhanced bandwidth estimation procedures within the congestion control scheme of TCP was proposed recently as a way of improving TCP performance over links affected by random loss. This paper first analyzes the problems faced by every bandwidth estimation algorithm implemented at the sender side of a TCP connection. Some proposed estimation algorithms are then reviewed, analyzing and comparing their estimation accuracy and performance. As existing algorithms are poor in bandwidth estimation, and in sharing network resources fairly, we propose TIBET (time intervals based bandwidth estimation technique). This is a new bandwidth estimation scheme that can be implemented within the TCP congestion control procedure, modifying only the sender-side of a connection. The use of TIBET enhances TCP source performance over wireless links. The performance of TIBET is analyzed and compared with other schemes. Moreover, by studying TCP behavior with an ideal bandwidth estimation, we provide an upper bound to the performance of all possible schemes based on different bandwidth estimates. 相似文献
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This paper proposes a new congestion control scheme of mobile Stream Control Transmission Protocol (mSCTP) for vertical handover
across heterogeneous wireless/mobile networks. The proposed scheme is based on the estimation of available bandwidths in the
underlying network as a cross-layer optimization approach. For congestion control of mSCTP, the initial congestion window
size of the new primary path is adaptively configured, depending on the available bandwidth of the new link that a mobile
node moves into. By ns-2 simulation, the proposed scheme is compared with the existing congestion control schemes in the throughput
perspective. From the numerical results, we can see that the proposed mSCTP congestion control scheme could give better performance
than the existing schemes in the wireless networks with an amount of background traffic. 相似文献