无线自组织网络中一种拥塞意识的多径路由算法

提出了无线自组织网络中一种拥塞意识的多径路由算法。该算法在路由发现过程中,综合节点的队列长度和路径跳数来动态确定路由请求消息的转发概率,可以在保证路由请求消息有一定送达率的条件下,降低路由开销;在路径选择和流量分配过程中,综合考虑节点的队列长度和路径质量作为路由度量,发现流量高吞吐量低拥塞路径,并基于该度量值进行流量分配。仿真结果显示,所提出的多径路由算法能有效提高网络性能。     

分组传送网的QoS实现方式分析

通过DifferServ模型介绍了分组传送网络的QoS实现策略,分析了流分类、流量整形、拥塞管理以及拥塞避免等QoS策略的技术实现方式,并对其进行优缺点比较。     

TCP-Shape:一种改进的网络拥塞控制算法研究

网络拥塞是由于网络业务流不可预测的流量突发现象造成的.文章从考虑网络业务流突发现象产生的特点出发,采用可用带宽测量技术和流量整形技术,提出了一种针对传统网络拥塞控制算法的改进算法(TCP-Shape).改进后的拥塞控制算法能够快速地探测到网络链路中可用剩余带宽并能够有效地消除网络业务流中的突发现象.使得在网络业务流的吞吐量和数据报文段的丢失率等性能上,更加优越于传统拥塞控制算法所获得的性能.     

多业务接入系统流量管理技术及其实现

通过分析基于ATM的多业务接入系统对流量管理的要求 ,对大唐电信光通信分公司开发的基于ATM的多业务接入系统 (LinkMasterA - 10 0 )中采取的流量管理技术 ,包括连接接纳控制、使用参数控制、加权公平排队、拥塞控制、帧丢弃、流量整形等算法及其具体实现进行了介绍与探讨     

HSDPA网络中基于虚拟队列的Iub流量控制

随着UMTSHSPA+技术的发展以及上下行峰值速率的不断增加,无线接入网络拥塞日益严重。由于底层重传协议的存在,TCP的拥塞控制方法不能有效解决HSDPA网络中的拥塞问题。3GPP定义了HSDPA流量控制算法,但该算法仅解决了空中接口的拥塞问题。本文提出了基于虚拟队列的流量控制方法,旨在解决Iub传输网络的拥塞问题。系统分析和性能仿真证明了该算法能有效地规避网络拥塞导致的RLC实体重传,从而提高Iub传输链路的吞吐量,并且传输时延和丢包的情况也不会恶化。此外,该算法可以针对运营商的具体服务质量(QoS)需求进行调节。     

基于控制论的ATM拥塞控制算法

ATM网络的多业务复用特性及其对QoS的承诺,使得其流量和拥塞控制变得非常复杂。控制论是分析和设计复杂系统的强有力工具,文章运用控制理论闭环反馈理论,设计了PI调节器,实现了基于PI调节器的ATM拥塞控制算法,实验及理论分析结果表明,该算法具有较强的稳定性与鲁棒性。     

多目标的Internet路由优化控制算法

研究通过优化链路权值以控制网络路由来实施流量工程.以网络拥塞最小化和时延最小化为流量工程目标,建立了多目标的全局路由优化数学模型.求解该问题是NP困难的,提出一种混沌群搜索优化算法进行求解.算法采用群局部搜索,利用混沌变量产生一组分布好的初始解,并在邻域搜索进程中应用扩展贪心思想,提高了算法的全局搜索能力.仿真结果表明所提算法能够有效减少由于流量分布不平衡造成的网络拥塞,同时限制长路径,提高了网络性能.     

基于模糊逻辑的无线网络流量自适应控制

文章在分析现有提高无线TCP性能方案的基础上，提出一种新的流量控制方法，即基于显式窗口反馈的无线网络流量控制方案。在Snoop中引入有线网络的显示窗口自适应（EWA）算法，通过对BS共享缓存的实时监测，应用模糊控制算法预测当前拥塞窗口（cwnd）的大小，并显式反馈给发送端，使TCP的发送窗口能快速响应网络负荷状况的变化．避免分组的丢失。仿真结果表明．该方法增强了网络对拥塞的自适应性以及对无线信道差错的实时处理能力．提高了网络的吞吐量。     

基于MAC层速率调整的无线Mesh网络拥塞控制

为了解决无线Mesh网络的拥塞问题,从MAC层出发,设计了一套拥塞控制方案(Data Link Congestion Control,DLCC),通过自定义协议实现拥塞时的消息反馈,采用令牌桶算法限制Mesh节点下发的流量。最后分析对比了使用方案前后的网络吞吐量,验证了算法存在性能增益。     

基于价格调整和流量工程的软件定义数据中心网络传输优化方法

分析数据中心网络动态价格调整拥塞控制和流量工程传输优化方法的研究现状,提出结合拥塞控制、流量调度和负载均衡的网络传输优化方法,设计一种新型数据中心网络资源动态价格调整策略框架,构建一种两层结构的数据中心网络拥塞控制价格设置算法,平衡和调节各发送端的购买力和链路带宽收益之间的关系,根据各价格指标设计具有QoS路由技术与调度算法实现资源优化利用的流量工程方法,扩展OpenFlow协议算法,整合SDN、FAST协议、ECN三种技术,从运行机制方面找到提高数据中心网络传输性能的方法.     

传感器网络变权组合预测流量整形算法

针对现有流量整形算法在传感器网络应用上的不足,提出了一种新的流量整形算法。分析了传感器网络流量具有突发随机性以及时变不均衡性的原因,根据传感器网络流量的模糊性、随机性以及时变性统一建模,提出了变权组合预测流量整形算法（TSAV,Traffic Shaping Algorithm with Variable weight combination forecast）,该算法通过逼近最优组合理论分配模糊AR预测与Kalman预测的组合权重,得到更为精确的预估流量值,提前规划整形速率从而平滑的输出分组流。实验表明,TSAV算法应用到传感器网络时能够准确预测流量,减少分组丢弃率的同时增大网络吞吐量,改善了传感器网络信息传输的QOS性能。      

基于卡尔曼滤波和小波的网络流量预测算法研究

流量预测是流量工程,拥塞控制和网络管理的核心问题。该文针对网络流量的特点,将卡尔曼滤波和小波分析混合的预测算法引入到网络流量预测领域中,对其进行了理论证明。仿真结果表明,该算法与传统的算法相比,具有较高的预测精度和较好的实时性与广谱性。     

Optimizing routing based on congestion control for wireless sensor networks

Along with the increasing demands for the applications running on the wireless sensor network (WSN), energy consumption and congestion become two main problems to be resolved urgently. However, in most scenes, these two problems aren’t considered simultaneously. To address this issue, in this paper a solution that sufficiently maintains energy efficiency and congestion control for energy-harvesting WSNs is presented. We first construct a queuing network model to detect the congestion degree of nodes. Then with the help of the principle of flow rate in hydraulics, an optimizing routing algorithm based on congestion control (CCOR) is proposed. The CCOR algorithm is designed by constructing two functions named link gradient and traffic radius based on node locations and service rate of packets. Finally, the route selection probabilities for each path are allocated according to the link flow rates. The simulation results show that the proposed solution significantly decreases the packet loss rate and maintains high energy efficiency under different traffic load.     

GSM phase 2+ general packet radio service GPRS: Architecture, protocols, and air interface

Selective packet dropping policies have been used to reduce congestion and transmission of traffic that would inevitably be retransmitted. For data applications using best-effort services, packet dropping policies (PDPs) are congestion management mechanisms implemented at each intermediate node that decide, reactively or proactively, to drop packets to reduce congestion and free up precious buffer space. While the primary goal of PDPs is to avoid or combat congestion, the individual PDP designs can significantly affect application throughput, network utilization, performance fairness, and synchronization problems with multiple Transmission Control Protocol (TCP) connections. Scalability and simplicity are also important design issues. This article surveys the most important selective packet dropping policies that have been designed for best-effort traffic in ATM and IP networks, providing a comprehensive comparison between the different mechanisms.     

最小化路径代价和流量均衡模型及算法

流量均衡是流量工程中为避免网络拥塞经常采用的路由优化目标,如何选择路径以使流量达到均衡分布是流量路由的研究热点和难点.为了最小化网络拥塞,该文在指出网络拥塞决定于流量路由时所选路径的拥塞特征后,建立了流量分布的最小化路径代价和模型.在流量路由选择路径时,提出基于瓶颈链路的最小代价路径路由算法.在实际的网络拓扑和流量矩阵数据基础上对所提模型及算法进行了实验验证,结果显示:在网络负载较大时最大链路利用率相对于已有模型可降低近20%.     

Towards Robust Multi-Layer Traffic Engineering: Optimization of Congestion Control and Routing

In the Internet today, traffic engineering is performed assuming that the offered traffic is inelastic. In reality, end hosts adapt their sending rates to network congestion, and network operators adapt the routing to the measured traffic. This raises the question of whether the joint system of congestion control (transport layer) and routing (network layer) is stable and optimal. Using the established optimization models for TCP and traffic engineering as a basis, we find the joint system can be stabilized and often maximizes aggregate user utility. We prove that both stability and optimality of the joint system can be guaranteed for sufficiently elastic traffic simply by tuning the cost function used for traffic engineering. Then, we present a new algorithm that adapts on a smaller timescale to changes in traffic distribution and is more robust to large traffic bursts. Uniting the network and transport layers in a multi-layer approach, this algorithm, distributed adaptive traffic engineering (DATE), jointly optimizes the goals of end users and network operators and reacts quickly to avoid bottlenecks. Simulations demonstrate that DATE converges quickly     

Performance analysis of reactive congestion control for ATMnetworks

In ATM networks, preventive congestion control is widely recognized for efficiently avoiding congestion, and it is implemented by a conjunction of connection admission control and usage parameter control. However, congestion may still occur because of unpredictable statistical fluctuation of traffic sources even when preventive control is performed in the network. The authors study another kind of congestion control, i.e., reactive congestion control, in which each source changes its cell emitting rate adaptively to the traffic load at the switching node (or at the multiplexer). The intention is that, by incorporating such a congestion control method in ATM networks, more efficient congestion control is established. They develop an analytical model, and carry out an approximate analysis of reactive congestion control algorithm. Numerical results show that the reactive congestion control algorithms are very effective in avoiding congestion and in achieving the statistical gain. Furthermore, the binary congestion control algorithm with push-out mechanism is shown to provide the best performance among the reactive congestion control algorithms treated     

Managing bandwidth in ATM networks with bursty traffic

Three approaches to the bandwidth management problem that have been proposed and studied by various groups are reviewed to illustrate three distinctly different approaches and identify their strengths and weaknesses. Based on these approaches, a bandwidth management and congestion control scheme for asynchronous transfer mode (ATM) networks that supports both point-to-point and one-to-many multicast virtual circuits is proposed. It is shown that the method can handle fully heterogeneous traffic and can be effectively implemented. The algorithm for making virtual circuit acceptance decisions is straightforward and fast, and the hardware mechanisms needed to implement buffer allocation and traffic monitoring at the user-network interface have acceptable complexities. It is also shown, through numerical examples, that the approach can achieve reasonable link efficiencies even in the presence of very bursty traffic. No advance reservation required, simplifying the interface between the network and the user and avoiding an initial network round trip delay before data can be transmitted     

Cooperative congestion control schemes in ATM networks

One of the basic problems faced in the design of efficient traffic and congestion control schemes is related to the wide variety of services with different traffic characteristics and quality of service (QoS) requirements supported by ATM networks. The authors propose a new way of organizing the control system so that complexity is easier to manage. The multi-agent system approach, which provides the use of adaptative and intelligent agents, is investigated. The authors show, through the two congestion control schemes proposed, how to take advantage of using intelligent agents to increase the efficiency of the control scheme. First, TRAC (threshold based algorithm for control) is proposed, which is based on the use of fixed thresholds which enables the anticipation of congestion. This mechanism is compared with the push-out algorithm and it is shown that the authors' proposal improves the network performance. Also discussed is the necessity of taking into account the network dynamics. In TRAC, adaptative agents with learning capabilities are used to tune the values of the thresholds according to the status of the system. However, in this scheme, when congestion occurs, the actions we perform are independent of the nature of the traffic. Subsequently, we propose PATRAC (predictive agents in a threshold based algorithm for control) in which different actions are achieved according to the QoS requirements and to the prediction of traffic made by the agents. Specifically, re-routing is performed when congestion is heavy or is expected to be heavy and the traffic is cell loss sensitive. This re-routing has to deflect the traffic away from the congestion point. In this scheme, we propose a cooperative and predictive control scheme provided by a multi-agent system that is built in to each node