一种基于动态部分缓存共享机制的RED改进

提出了一种基于动态部分缓存共享机制的随机早期检测(RED)拥塞控制改进方案，并给出了算法实现，最后通过仿真进行了性能分析，验证其为区分服务的不同性能要求提供了拥塞控制功能。     

通信网络中的拥塞控制

介绍了网络中发生拥塞带来的问题，TCP／IP的拥塞控制和常用的减少拥塞的几种措施；讨论了拥塞管理的算法并介绍了2种拥塞避免的算法，即随机早期检测(RED)算法和加权随机早期检测(WRED)算法；说明了参数选择的依据，并简单描述了在大型TCP／IP网络中运用WRED算法的意义。     

一种无线网络中基于ARQ的拥塞控制方法

提出了一种适用于无线网络的基于多拒绝自动请求重传（ARQ）算法的拥塞控制方法。谊方法结合随机早探洲（RED）算法，通过ARQ发送窗口和分割队列长度以及重传率进行拥塞控制。仿真表明，这种方法能预测链路拥塞，反馈链路拥塞程度，提高链路吞吐率。     

一种新的语音流队列管理调度机制

本文提出一种新的语音流队列管理调度机制,结合随机早期探测(RED)和主动丢包调度算法实现因特网语音流的队列管理和调度.采用仿真方法分析了新机制的性能特征,并与RED做了性能对比.当网络拥塞时,该算法可有效改善包转发的性能.语音质量测试表明新机制是可行的和有效的.     

无线Mesh网络中基于链路负载估算的拥塞控制策略

针对无线Mesh网络的网络特性,提出了一种基于链路负载估算的拥塞控制策略LLECC。LLECC算法计算有效链路带宽和链路负载估算确定RED算法中的调整因子,通过调整因子调整RED算法中的参数从而实现动态的对无线网络拥塞控制。详细讨论了LLECC算法的实现过程和相关参数的计算方法,通过仿真分析验证了该算法对无线Mesh网络性能的提高。     

动态权重RED网关

随着网络流量的增加,拥塞控制的重要性日益突出,尤其是链路拥塞控制。IETF推荐RED(Random Early Detection)作为下一代Internet路由器的拥塞控制算法。该文在分析了RED的优点和缺点后,在现在RED算法的基础上通过改进RED算法的平均队列长度计算,使用平均队列长度的均值,判断拥塞的发生和结束,动态调整权重,提高RED对拥塞发生和拥塞结束的反应速度,缩短拥塞时间,维持较低的实际队列长度。最后用仿真验证了该方法。     

基于2-D稳定条件的混合流网络参数设置

由于网络容量的限制,任何一个网络都不可能避免拥塞问题。传统的RED算法只考虑了少量TCP用户,没有涉及UDP用户的情况,同时随着网络应用的多样化,如越来越多的UDP用户接入网络,传统的RED机制无法控制它们,保证不了TCP用户的服务质量(QoS)。针对TCP/UDP混合流多用户的情况,本文提出TCP/UDP混合流的区分控制,这里TCP和UDP流使用不同的带宽,及TCP/UDP混合流单瓶颈网络的2-D稳定条件。基于该稳定条件可以选择一个合适的RED控制参数Pmax,获得满意的网络拥塞控制性能。本文建立了一个TCP和UDP流单瓶颈网络的线性时滞系统模型,利用2-D拉普拉斯-Z变换,推导出基于稳定条件的混合流网络参数配置。利用NS2仿真验证所提出的混合流网络参数配置能够有效获得关于路由器队列长度和TCP窗口的稳定性。     

对TCP/IP计算机网络拥塞控制的研究

为提升计算机的网络性能,更好地避免拥塞现象的发生,需要对其进行必要的技术控制。鉴于此,对基于TCP/IP协议的网络拥塞控制方法进行分析。在TCP拥塞控制中主要采用TCP Tahoe,TCP Reno,TCP New Reno以及TCP Sack四种方法,其中TCP New Reno对快速恢复算法进行了改进,通过对TCP协议中的Reno进行可视化处理,实行对网络拥塞的有效管理。而IP拥塞控制方法则分为FIFO,FQ和WFQ,RED以及ECN四种类型,通过队列调度管理方式实现了对网络拥塞的有效管理。     

一种参数自适应的主动队列管理算法-自适应BLUE

BLUE算法是一种典型的主动队列管理(Active Queue Management,AQM)算法,研究表明BLUE算法优于RED算法.BLUE算法使用丢包事件和链路空闲事件控制网络拥塞.但由于BLUE算法在参数设置方面存在不足,尤其是当TCP连接数突然剧烈变动时,容易导致队列溢出或空闲的频繁发生.该文引进参数自适应机制,提出了自适应BLUE算法,并借鉴了RED算法的早期拥塞检测机制.NS仿真实验表明该算法能有效保持队列长度的稳定,减少队列溢出或空闲现象的发生,在提高链路利用率的同时降低丢包率.     

基于RED的AODV路由协议改进

基于当前使用非常广泛的随机早期检测（RED）拥塞控制机制，提出了一种改进方案：在AODV的路由发现阶段，根据当前平均队列长度来确定以不同的方式响应路由请求，从而使建立起来的路由比较可靠，使数据流可以绕过负担比较重的节点，实现一定程度的拥塞控制和流量均衡，最后对改进前后的协议进行了性能仿真和分析。结果表明，改进后的协议与原协议相比在复杂度没有明显增加的前提下，降低了平均延时和丢包率，提高了网络性能。     

RELD, RTT ECN Loss Differentiation to optimize the performance of transport protocols on wireless networks

One major yet unsolved problem in wired-cum-wireless networks is the classification of losses, which might result from wireless temporary interferences or from network congestion. The transport protocol response to losses should be different for these two cases. If the transmission uses existing protocols like TCP, the losses are always classified as congestion losses by sender, causing reduced throughput. In wired networks, ECN (Explicit Congestion Notification) can be used to control the congestion through active queue management such as RED (Random Early Detection). It can also be used to solve the transport protocol misreaction over wireless networks. This paper proposes a loss differentiation method (RELD), based on ECN signaling and RTT (Round Trip Time), and applied to TCPlike. TCPlike is one of the three current congestion controls present in the new transport protocol DCCP (Datagram Congestion Control Protocol). Our simulations, using a more realistic simulated loss error model for wireless networks, show that RELD optimizes congestion control and therefore increases the performance of transport protocols over wireless networks, leading to an average performance gain ranging from 10% to 15%.     

A fuzzy-logic control algorithm for active Queue Management in IP networks

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.     

Robustness of real and virtual queue-based active queue management schemes

In this paper, we evaluate the performance of both real and virtual queue-based marking schemes designed for use at routers in the Internet. Using fluid flow models, we show via analysis and simulations that Virtual Queue (VQ)-based marking schemes outperform Real Queue (RQ)-based marking schemes in terms of robustness to disturbances and the ability to maintain low queueing delays. In fact, we prove that a linearized model of RQ-based marking schemes exhibit a lack of robustness to constant but otherwise unknown levels of disturbances. The analytical results we present are applicable to combinations of proportionally fair and TCP-type congestion controllers at the source, and Random Exponential Marking (REM) and Proportional Control (PC) schemes at the router. The behavior of Random Early Discard (RED) and Proportional-Integral (PI) control schemes at the router are also studied via simulations.     

An Improved Algorithm of Nonlinear RED Based on Membership Cloud Theory

Concerning on the shortcoming and com-plexity of Random early detection (RED) algorithm in net-work congestion control, a new RED algorithm based on the Hemi-Rise Cloud model (CRED) was proposed, non-linear packet loss strategy was used, and sensitivity and un-certainty of parameters were improved. As a result, queue length could be kept stable in the neighborhood of ref-erence value. Network congestion was well controlled and network resource was used effectively. The stability of the algorithm was studied and the experimental results showed that the proposed algorithm could improve the stability, and had better performance than the RED and Adaptive RED (ARED) algorithms.     

Internet connection with UMTS

Mobile telecommunication new services are based on data networks specially Internet. These services include http, telnet, ftp, Simple Mail Transfer Protocol, etc. Besides, we recognize a mobile network as a multiuser network. Transmission Control Protocol (TCP)/Internet Protocol which is sensitive to link congestion in wireline data links is also used in wireless networks. In order to improve the system performance, the TCP layer uses flow control and congestion control. Besides, radio link control (RLC) and medium access control sublayers have been introduced to compensate the deficiency of TCP layer in wireless environment. RLC has an important role in quality of service enhancement of the Universal Mobile Telecommunications System (UMTS). In this paper, we review the protocol stack of UMTS Terrestrial Radio Access Network which is based on Third-Generation Partnership Project. Then, we evaluate its layer 2 error control mechanisms and verify TCP over automatic repeat request error control mechanism and finally quality of service improvement results from it in fading channels.     

A framework to determine the optimal weight parameter of RED in next‐generation Internet routers

Active buffer management can improve the performance of Transmission Control Protocol/Internet Protocol‐based networks. Random early detection (RED), an active queue management scheme, has been proposed by the Internet Engineering Task Force for next‐generation Internet routers. RED uses a number of parameters, such as buffer thresholds, a packet drop probability and a weight parameter. RED suffers from low throughput and large delay/jitter and induces instability in networks. Previous attempts to improve the performance of RED were based on modifying the thresholds and drop probabilities. In this paper, we show that an optimal value of the weight parameter can improve the performance of RED, and then develop a framework to determine the optimal value of the weight parameter. We show that the optimal weight parameter obtained from our framework improves the performance of RED. Copyright © 2008 John Wiley & Sons, Ltd.     

几种主动式队列管理算法的比较研究

主动式队列管理(Active Queue Management,AQM)技术是IETF为了解决Internet拥塞控制问题而提出的一种路由器缓存管理技术.本文对几种主要AQM算法RED、BLUE、ARED和SRED的性能在基于ns-2仿真实验的基础上进行了比较研究.研究的性能包括队列长度、丢包概率、丢包率、连接数对吞吐量的影响及缓冲区大小对链路利用率的影响等.仿真结果表明BLUE、ARED和SRED在这几方面的性能都要优于RED算法.     

基于链路资源改进RED算法研究

Internet上随着网络的不断发展和用户的要求越来越高,以为用户提供更高服务质量（Quality of Service,QoS）为目标的研究越来越重要。而强壮的网络拥塞控制是保障用户服务质量的基础。“随机早期检测算法”（Random Early Detection,RED）[1],由于其在实际应用的广泛,成为研究热点。文章首先探讨远端流和近端流在在传输过程中的不公平性和链路资源利用情况,在此基础上提出路由器将网络中的流分为远近两种区分对待,改进RED算法以提高链路资源的利用率和流在传输过程中的公平性。