ATM 网络预测拥塞控制器设计

网络传输中存在严重的不确定性，由此限制了常规反馈拥塞控制算法的应用．利用预测控制方法，设计出一种改进的拥塞控制算法，增强了闭环系统的鲁棒性和稳定性，实现了带宽分配的公平性．仿真结果证实了所提出方法是有效性的。     

多通道ATM 网络鲁棒拥塞控制

拥塞控制对ATM网络有效、稳定运行具有重要的作用，在单瓶颈多通道的网络模型下，基于Smith预估原理，提出一种新颖的鲁棒拥塞控制器设计方案，这种基于速率的拥塞控制可以保证ABR的服务质量(QoS)，理论分析和仿真结果表明，所提出方案收敛速度快，对网络的不确定因素具有较强的鲁棒性。     

A proportional feedback scheme for ATM networks

Available bit rate (ABR) service class is proposed by Asynchronous Transfer Mode (ATM) Forum to provide the “best-effort” services like traditional TCP/IP traffic. It is designed to make use of the remaining bandwidth not used by VBR and CBR. However, the bursty nature of ABR traffic makes it difficult to prevent buffers on ATM switches from overflowing. A number of schemes have been proposed for ABR traffic control. In this paper, a proportional scheme that is rate-based hop-by-hop flow control is proposed. A mathematical model is built to analyze the hop-by-hop flow control scheme. It is shown the scheme can utilize full bandwidth without any cell loss. It is also shown the scheme has low queuing delay and fast transient response.     

A rate-based flow control mechanism for avoiding congestion

The rate-based flow control mechanisms for the Available Bit Rate(ABR)service are used to share the available badwidth of a bottleneck switch connected to a bottleneck link fairly and reasonably among many competitive users,and to maintain the buffer queue length of the witch at a desired level in order to avoid congestion in Asynchronous Transfer Mode(ATM)networks.In this Paper,a control theoretic approach that uses a Deadbeat-Response(DR) controller to the desing of a rate-based flow control mechanism is presented.The mehanism has a simple structure and is robust in the sense that its stability is not sensitive to the change of the number of active Virtual Connections(VCs),Simulation results show that this mechanism not only ensures fair share of the bandwidth for all active VCs regardless of the nmuber of hops they traverse but also has the advantages of fast convergence ,no oscillation,and high link bandwidth utilization.     

ATM网络基于ABR服务的流量控制算法及其研究

讨论了在ATM网络中ABR业务拥塞控制机制及其改进方法,即在增强比例速率控制算法（EPRCA）中通过检测缓存队列长度来控制网络拥塞,大大降低了拥塞产生的可能性,防止了网络拥塞的崩溃,并提高了缓存的利用率.     

Analysis of Source Rate Adaption for ATM networks using a dynamic flow model

This paper focuses on using Source Rate Adaption (SRA) as a viable flow control scheme in Asynchronous Transfer Mode (ATM) networks. A modeling technique related to conducting performance evaluation studies using a dynamic flow model has been developed. SRA control strategies at node, domain or network levels have been proposed. Computer simulations verify the validity of the model and strategies.     

The sticky buffer flow control for the ATM

Data from different applications — voice, video, file transfer, interactive — will be multiplexed in the future over broadband integrated services digital networks (BISDN). Data are segmented into 48-byte blocks prefixed by a 5-byte header and transported over the network using the asynchronous transfer mode (ATM).

An ATM connection-request is a contract between the user and the network; the user specifies a rate requirement, delay constraints, a bound on the cell-loss probability and other quality of service parameters. If the network can meet these requirements, a connection is made. Bursty traffic producing peak traffic rates in excess of the projected average rate could result in congestion and lead to performance degradation. As a result, the network might no longer be able to deliver the negotiated quality of service to existing connections. To lessen the chance of congestion, input rate control must be implemented.

This paper contains a performance analysis of the sticky buffer (SB), a moving window input rate control scheme intended to limit the rate at which input traffic may enter a network. Policing is achieved by buffering and hence delaying the entry of ATM-cells into the network. The scheme is determined by parameters (R,T) which specify that no more than R ATM-cells are permitted to enter the network in every window of size T cells. We present an exact analysis, deriving the probability generating function of the queue length distribution. A comparison with the leaky bucket is given. Our numerical examples show the required buffer size is comparable to that required by the leaky bucket.     

Binary ABR flow control over ATM networks with uncertainty using discrete-time variable structure controller

A binary available bit rate (ABR) scheme based on discrete-time variable structure control (DVSC) theory is proposed to solve the problem of asynchronous transfer mode (ATM) networks congestion in this paper. A discretetime system model with uncertainty is introduced to depict the time-varying ATM networks. Based on the system model, an asymptotically stable sliding surface is designed by linear matrix inequality (LMI). In addition, a novel discrete-time reaching law that can obviously reduce chatter is also put forward. The proposed discrete-time variable structure controller can effectively constrain the oscillation of allowed cell rate (ACR) and the queue length in a router. Moreover, the controller is self-adaptive against the uncertainty in the system. Simulations are done in different scenarios. The results demonstrate that the controller has better stability and robustness than the traditional binary flow controller, so it is good for adequately exerting the simplicity of binary flow control mechanisms.     

基于参数自适应的ATM流量控制的研究

论文在总结各种ATM网络流量控制方法的基础上提出了一种参数自适应控制方法。该方案法对系统信元传输的不确定时延和不确定源节点数实现估计,并在保证参数全局稳定收敛的基础上提出了新的控制律。仿真结果证明了该方法的有效性。     

A cell spacing device for congestion control in ATM networks

In this paper, we study a cell spacing method of congestion control in ATM networks. The idea is to smooth the input flows at the access nodes in order to prevent cells from entering the network in a manner that could affect its performance. We consider a queueing system that prevents any two successive cells from being transmitted within a time shorter than a variable value. This device does not interfere with cells that find the queue empty and arrive a sufficiently long time after the last departure but spaces apart those which arrive too closely to each other. We analyze the statistical properties of the output traffic of such a cell spacer when the input process is modeled as a Compound-MMPP.     

基于Additive2multipl icative 模糊 神经网的ATM 网络拥塞控制

考虑了模糊神经网络的学习功能，提出利用Additive-multiplicative模糊神经网络(AMFNN)对ATM网络进行拥塞控制的方案．在拥塞控制过程中，利用AMFNN模糊神经网络预测下一个将要到达流的特征，结合当前缓冲区的队列信息预测网络是否发生拥塞．一旦预测出将有拥塞发生，控制器则向源端反馈拥塞控制信息，信源根据拥塞信息适当降低传输速率，从而避免了拥塞的发生．仿真结果表明，该方法可改善网络对拥塞的实时处理能力，提高网络资源的利用率．     

Ping-pong flow control for ATM ABR traffic

In this paper, we propose an improved technique for congestion control, named as ping-pong flow control (PPFC), for asynchronous transfer mode (ATM) available bit rate (ABR) traffic. This is a rate-based flow control scheme, in which the rate regulation is achieved by directly adjusting the transmission rate in the source end station. The proposed algorithm uses a bipolar feedback strategy, which employs positive and negative feedbacks to control the transmission rate for different switch states. These states are determined using the traditional threshold-based method. We also introduce state early detection (SED), which enables the PPFC to control traffic flows more precisely and accurately at critical moments. The simulation results show that the proposed algorithm provides a higher throughput and lower cell loss ratio when compared to the well-known backward explicit congestion notification (BECN). Furthermore, these results also show that PPFC is robust against feedback losses.     

ATM网络中ABR业务的拥塞控制

基于信用的拥塞控制和基于速率的拥塞控制方式各有优缺点,本文在讨论了几种主要的拥塞控制方式之后,提出了对OSU算法的改进方案。     

ATM网络中基于ABR业务的闭环拥塞控制

论文讨论了ATM网络中ABR业务的特性及基于ABR业务的拥塞控制机制,论述了拥塞控制技术的最新发展情况,并比较了各种控制机制的优缺点。     

Routing with admission control in ATM networks

An optimal control parameter, , was developed by optimal control theory for Asynchronous Transfer Mode (ATM) networks. The parameter is related to link utilization, buffer occupancy, system throughput and cell rejection characteristics and is applied to routing and admission control in simulation of a network carrying multiclass traffic. Simulation results show that the parameter produces better performance with respect to cell rejection rate characteristics compared with the traditional control parameter for utilization, .This research has been supported by the ATI as part of the Navy Contract N00140-94-C-BC03. Some parts of the paper were presented at Globecom'94.     

Binary ABR flow control over ATM networks with uncertainty using discrete-time variable structure controller

A binary available bit rate （ABR） scheme based on discrete-time variable structure control （DVSC） theory is proposed to solve the problem of asynchronous transfer mode （ATM） networks congestion in this paper. A discrete-time system model with uncertainty is introduced to depict the time-varying ATM networks. Based on the system model, an asymptotically stable sliding surface is designed by linear matrix inequality （LMI）. In addition, a novel discrete-time reaching law that can obviously reduce chatter is also put forward. The proposed discrete-time variable structure controller can effectively constrain the oscillation of allowed cell rate （ACR） and the queue length in a router. Moreover, the controller is self-adaptive against the uncertainty in the system. Simulations are done in different scenarios. The results demonstrate that the controller has better stability and robustness than the traditional binary flow controller, so it is good for adequately exerting the simplicity of binary flow control mechanisms.     

ATM网络中的ABR业务管理

该文介绍了ＡＴＭ网络中的一种新业务ＡＢＲ业务的管理及其最新发展，讨论了ＡＢＲ业务的管理模型，包括业务管理的目标，带宽分配，ＡＢＲ业务的拥塞控制机制及ＡＢＲ业务的特性等。     

Jitter in ATM networks and its impact on peak rate enforcement

Cells arriving to an ATM network experience random delays due to queueing in upstream multiplexing stages, notably in customer premises. This is the phenomenon of jitter and the aim of the present paper is to study its influence on peak rate enforcement. We first introduce some general characterizations of jitter and then, describe two models of jittered flows based on simple queueing systems. We discuss the objectives of peak rate enforcement and study the impact of jitter on the dimensioning of jumping window and leaky bucket mechanisms. A useful synthetic characterization of jitter appears to be a remote quantile of the cell delay distribution expressed in units of the initial inter-cell interval.     

ATM网络ABR业务拥塞控制算法的PI调节器实现

基于速率反馈的流量控制是ATM网络ABR业务标准的流量控制方案。在目前绝大多数拥塞控制方案不能用数学工具进行分析的情况下,本文根据经典控制理论的有关原理,使用一个PI控制器实现了拥塞控制算法。我们对系统进行了分析,证明了此时系统带宽和输入数据速率之间将是无差的;最后通过仿真说明了控制器参数的变化对系统的影响。