共查询到19条相似文献,搜索用时 109 毫秒
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主动队列管理 (ActiveQueueManagement,AQM)技术作为Internet拥塞控制的一种有效方法 ,对于提高In ternet的服务质量具有十分重要的作用 .本文根据TCP拥塞控制算法基于数据包丢失的窗口变化机制 ,设计了一种基于模糊逻辑的主动队列管理算法 .该算法依据路由器中队列长度的变化情况 ,根据一定的模糊自校正原则来调整数据包的丢弃概率 ,从而使路由器中的队列长度稳定在参考值附近 .仿真结果表明该算法不但十分有效 ,而且对不同的网络状况具有很好的适应能力 . 相似文献
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MBLUE(Modified BLUE)是一种面向数据流的活动队列管理算法.它不是使用平均队列长度指示缓冲区拥塞状态,而是使用数据报丢弃的频率和队列空闲程度来管理网络拥塞.探测瓶颈连接早期的拥塞信息,通过数据报的丢弃和标记避免拥塞.它只维护一个先进先出队列,以较少的数据流状态信息,在不同流之间公平的分配网络带宽.能够适应瞬时的猝发流,能合理控制非TCP数据流,又能够保持较短的平均队列长度,从而控制、减轻网络拥塞.通过TCP/IP网络的模拟,证实算法在公平的分配网络带宽和降低数据报的丢失率上具有较好的鲁棒性. 相似文献
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MPLS网络主动式流量和拥塞控制机制及性能分析 总被引:1,自引:0,他引:1
MPLS是具有大带宽一时延迟的网络,用传统的TCP解决MPLS拥塞问题显得十分困难,该文结合MPLS的网络特点,提出了一种适合MPLS网络的主动式流量和拥塞控制机制,在网络边缘节点引入拥塞反馈处理,对实验模型进行了性能仿真分析,实验证明,与传统的TCP协议相比,该机制将流量和拥塞控制从用户端点扩展到MPLS边缘路由器,能够更及时地检测和控制网络拥塞,缩短了控制时延,可以进行较精确的流量调节,实现了提高吞吐量和改善缓冲区利用率的目的。 相似文献
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一种基于模糊逻辑的主动队伍管理算法 总被引:2,自引:0,他引:2
主动队列管理(AciiveQueue Management,AQM)技术作为Internet拥塞控制的一种有效方法,对于提高Internet的服务质量具有十分重要的作用,本文根据TCP拥塞控制算法基于数据包丢失的窗口变化机制,设计了一种基于模糊逻辑的主动队伍管理算法,该算法依据路由器中队列长度的变化情况,根据一定的模糊自校正原则来调整数据包的丢弃概率,从而使路由器中的队列长度稳定在参考值附近,仿真结果表明该算法不但十分有效,而且对不同的网络状况具有很好的适应能力。 相似文献
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基于速率的主动队列管理算法的性能分析 总被引:1,自引:1,他引:1
主动队列管理是解决网络拥塞的主要措施。针对基于队列的主动队列管理算法的不足,提出了一种基于速率的新算法RAQM,该算法以数据到达速率与路由器最大服务速率的差值为指标计算丢包概率,能够快速地对网络流量的变化做出反应,该算法计算简单,而且只需要设置一个参数K。通过现代控制理论分析了RAQM/TCP系统的稳定性。仿真结果表明,RAQM能够维持较低的队列长度并保持队列的稳定,从而减小了分组端到端时延和时延抖动。最后讨论了参数K对算法性能的影响。 相似文献
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Seungwan Ryu 《International Journal of Communication Systems》2004,17(8):811-832
Two functions, the congestion indicator (i.e. how to detect congestion) and the congestion control function (i.e. how to avoid and control congestion), are used at a router to support end‐to‐end congestion control in the Internet. Random early detection (RED) (IEEE/ACM Trans. Networking 1993; 1 (4):397–413) enhanced the two functions by introducing queue length averaging and probabilistic early packet dropping. In particular, RED uses an exponentially weighted moving average (EWMA) queue length not only to detect incipient congestion but also to smooth the bursty incoming traffic and its resulting transient congestion. Following RED, many active queue management (AQM)‐based extensions have been proposed. However, many AQM proposals have shown severe problems with detection and control of the incipient congestion adaptively to the dynamically changing network situations. In this paper, we introduce and analyse a feedback control model of TCP/AQM dynamics. Then, we propose the Pro‐active Queue Management (PAQM) mechanism, which is able to provide proactive congestion avoidance and control using an adaptive congestion indicator and a control function under a wide range of traffic environments. The PAQM stabilizes the queue length around the desired level while giving smooth and low packet loss rates and high network resource utilization. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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FPI-PD-MCC:一种基于模糊PI-PD的组播拥塞控制算法 总被引:2,自引:1,他引:1
针对TFMCC算法速率振荡大的局限性,提出了一种基于模糊PI—PD的组播拥塞控制算法(FPI—PD—MCC:Fuzzy Logic—based Proportional Integral-proportional Derivatire Multicast Congestion Control Algorithm)。在FPI—PD—MCC中,对发送方的速率调整步长进行了平滑,在路由器中引入了PI控制,并利用模糊逻辑计算参数α,从而自动调节丢包概率以缓解拥塞。仿真结果表明,该算法能够使队列长度稳定在期望值附近,同时保证网络吞吐量的平缓变化。 相似文献
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Liu Weiyan Zhang Shunyi Zhang Mu Liu Tao 《电子科学学刊(英文版)》2008,25(1):102-107
Active Queue Management (AQM) is an active research area in the Internet community. Random Early Detection (RED) is a typical AQM algorithm, but it is known that it is difficult to configure its parameters and its average queue length is closely related to the load level. This paper proposes an effective fuzzy congestion control algorithm based on fuzzy logic which uses the predominance of fuzzy logic to deal with uncertain events. The main advantage of this new congestion control algorithm is that it discards the packet dropping mechanism of RED, and calculates packet loss according to a preconfigured fuzzy logic by using the queue length and the buffer usage ratio. Theoretical analysis and Network Simulator (NS) simulation results show that the proposed algorithm achieves more throughput and more stable queue length than traditional schemes. It really improves a router's ability in network congestion control in IP network. 相似文献
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As CDMA-based cellular networks mature, the current point-to-point links used in connecting base stations to network controllers evolve to an IP-based radio access network (RAN) for reasons of lower cost due to statistical multiplexing gains, better scalability and reliability, and the projected growth in data applications. In this paper, we study the impact of congestion in a best-effort IP RAN on CDMA cellular voice networks. We propose and evaluate three congestion control mechanisms, admission control, diversity control, and router control, to maximize network capacity while maintaining good voice quality. We first propose two new enhancements to CDMA call admission control that consider a unified view of both IP RAN and air interface resources. Next, we introduce a novel technique called diversity control that exploits the soft-handoff feature of CDMA networks and drops selected frames belonging to multiple soft-handoff legs to gracefully degrade-voice quality during congestion. Finally, we study the impact of router control where an active queue management technique is used to reduce delay and minimize correlated losses. Using simulations of a large mobile network, we show that the three different control mechanisms can help gracefully manage 10-40 percent congestion overload in the IP RAN. 相似文献
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用户公平的活动队列管理 总被引:2,自引:0,他引:2
用户公平活动队列管理算法UFQ(User Fair Queuing)的目标是在各种网络环境中都能为所有的用户提供满意度一致的服务.UFQ采用在网络边缘标记用户所属数据报的期望服务满意度u,在网络核心根据数据报的满意度高低,结合当前数据报流经节点的拥塞程度,来决定数据报的丢弃或标记(使用ECN),从而获得不同用户一致满意的服务.UFQ不要求接纳控制和信令.它仅在网络边缘保持数据流的状态信息;只维护一个先进先出队列,通过拥塞时丢弃或标记较高满意度的数据报,在不同的用户之间公平地分配网络带宽,从而有效地控制、减轻拥塞.通过TCP/IP网络的模拟,证实了算法能够按照用户期望满意度公平地分配网络带宽,提高网络的服务质量. 相似文献
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Fengyuan Ren Xunhe Yin Xiaomeng Huang Chuang Lin 《Communications Letters, IEEE》2006,10(12):858-860
Active queue management (AQM) is proposed to enhance end-to-end congestion control through purposefully dropping packets in the intermediate nodes. In this letter, a novel packet dropping mechanism is developed through designing a binary controller applying the robust control theory. The new mechanism can simplify the manipulation on the AQM router so as to be helpful for implementing the high performance router. The numerical simulation results show that the binary controller can satisfy with the technical requirements for AQM 相似文献