Hadoop平台下一种改进蚂蚁算法的QoS路由研究

随着未来云计算的发展,各种云服务的应用将需要更高的网络性能。链路拥塞导致的数据包传输时延或数据包丢弃使得网络无法保障业务的QoS。目前普遍使用的链路状态路由算法不具有拥塞响应机制。本文通过在拥塞节点间发送连接蚂蚁寻找新路由来解决拥塞问题。NS2仿真结果表明,该算法能加快新的路由搜索,满足QoS的需求,并有效控制丢包率,时延等性能。     

一种基于负载均衡的新型自适应路由算法

提出了一种用于波分复用(WDM)网络中的新型自适应路由算法.引入蚁群算法解决动态路由问题,通过改进寻路中链路综合权重的设置、优化蚁群寻路的原理以及考虑波长优先级来设计算法.仿真结果表明,这种算法对光通道建立比较有效,使用这种算法,不仅可以使拥塞率更小,负载分布也更加均衡.     

WiNoC中无线节点和无线链路级拥塞避免的高效路由器设计

无线片上网络中,无线网络拥塞可以分为无线节点级的拥塞和无线链路级的拥塞,这两种拥塞都会造成网络性能下降.针对无线节点和无线链路级拥塞,本文设计了一种拥塞避免的高效无线路由器,首先提出了节点级的拥塞避免机制,无线节点通过广播本地拥塞信息相互感知拥塞程度,避免向拥塞程度较高的无线节点发送数据包;其次提出了链路级拥塞避免机制,在无线接口中设计了并行FIFO,允许无线接口以流水的方式,在单个时钟周期内传输一个拥塞信息数据包和三个数据微片,数学建模证明使用并行FIFO至少降低50%无线信道竞争频率,从而避免了无线链路级拥塞,提高了无线资源利用率.实验表明本文方案相较普通无线路由器增加了少量的面积,但是在网络整体性能、无线路由器性能以及功耗方面都取得了不错的优势.     

基于SDN的数据中心链路均衡算法研究

针对当前数据中心网络存在链路利用率低,容易产生拥塞以及更新部署新兴业务周期长的缺点。本文将SDN（software define network）架构应用到数据中心网络中,并提出了一种链路负载均衡算法LLB,该算法基于链路的利用率为数据包选择负荷较轻的路径并由控制器以流表的形式下发。试验证明该算法能有效提高链路的利用率,缓解拥塞现象,提高资源利用率。     

传感器网络拥塞避免与控制的模糊AQM算法

传感器网络节点通信能力有限,当数据到达速率持续超过节点转发能力时网络会发生拥塞;传感器网络是任务型网络,对不同优先级的信息具有不同的服务质量要求.针对传感器网络信息传输的上述特性,提出了一种新的拥塞避免与控制算法FAQM（Fuzzy Active Queue Management）.该算法在综合考虑数据包的随机指数标记概率和优先级权值的基础上,建立了模糊逻辑推理系统,并以数据包丢弃因子作为参量来实现数据流的智能调控.NS2仿真实验结果表明：FAQM算法能减少高优先级数据包的丢弃率和节点间链路的时延,稳定节点队列长度,在有效避免与控制拥塞网络的同时提升网络整体QoS（Quality of Service）性能.     

WiNoC中交叉开关仲裁及路由算法设计

WiNoC(Wireless Network-on-Chip)中的无线路由器面临着比传统片上路由器更加严峻的拥塞问题,平衡有线/无线链路负载是当前无线片上网络的研究热点之一.为此本文提出并设计了一种基于优先级的交叉开关仲裁方案PbSA(Priority based Switch allocator),其将优先级更高的无线数据包优先路由至无线路由器;结合PbSA提出了拥塞感知的路由算法CARA(Congestion-Aware Routing Algorithm),该算法有效平衡有线/无线链路负载且避免死锁,提高了数据包在网络中的路由效率.此外,本文还提出了新颖的虚通道划分方法,它不仅减少了实现PbSA的硬件复杂度,而且缓解了无线路由器发生拥塞时对整个网络的影响.实验表明,虽然本文的方案引入了较小的面积和功耗开销,但是具有良好的流量自适应特性,从而在低注入率或高注入率的情况下较好的提升了网络性能.     

基于蚁群算法的分布式卫星光网络波长路由分配技术研究

为了解决分布式卫星光网络波长路由分配复杂的问题,论文提出基于小窗口策略的蚁群优化算法。采用链路可持续时间和波长空闲率作为启发函数,在实现负载均衡的同时,降低网络的拥塞率;引入小窗口策略引导蚂蚁在最小路由请求区域内进行选路,提高了算法的收敛速度;通过计算相邻链路空闲波长的交集,实现了由单只蚂蚁同时完成路由选择和波长分配。对单主星和双主星两种场景下的算法性能进行了仿真分析,结果表明:与经典的Dijkstra+FF算法相比较,单主星和双主星时的网络拥塞率最高分别降低了0.5和0.7,网络资源利用率改善最高可达到0.45和0.50。     

基于负载均衡的智能光网络路由算法

提出了基于负载均衡的路由算法的思想能够缓解网络因为过多的使用某条链路而引起的拥塞和较少使用某条链路而导致的资源浪费等问题,并且把此算法运用到智能光网络中去.     

在Ad Hoc网络中TCP-SACK性能研究及改进

在Ad Hoc网中,经常发生链路失效和路由变化。TCP把数据包的丢失归结为链路拥塞,所以TCP在Ad Hoc网中表现很差。在本文中通过应用一种新的方法,基于传输包乱序检测与响应方法,研究TCP在Ad Hoc网中的性能。通过实验结果表明,此算法解决了,提高了网络的吞吐量。     

移动自组网中新的智能丢包区分机制

为了有效区分移动自组网中由于网络拥塞、路由切换和链路错误引起的丢包,通过模糊计算的综合评判模型,在发送端综合端到端往返延时、短期的吞吐量以及乱序数据包3个网络观测参数进行判断。仿真结果表明智能丢包区分算法对丢包原因的判断取得了较好的效果。基于该智能丢包区分算法的TCP改进方案TCP-Fuzzy,能够根据判断出的丢包原因采取恰当的拥塞控制策略,在各种不同的网络环境下都有较好的性能表现。     

软件定义卫星光网络蚁群优化波长路由技术

针对卫星光网络中网络拓扑动态时变和业务类型多样化的问题,研究了在软件定义网络架构下保障服务质量的路由技术,提出了一种基于多业务的卫星光网络蚁群优化波长路由算法。通过改进蚁群算法的启发函数,将波长空闲率、时延、时延抖动、丢包率作为蚂蚁选路的重要依据,为业务选择了满足多种服务质量的最优路径;采用分组波长分配方法对不同等级的业务进行了区分服务,为不同业务分配了不同的波长集。仿真结果表明:与CL-ACRWA算法和Dijkstra算法相比,降低了卫星光网络的平均时延、平均时延抖动、平均丢包率,提高了波长利用率,同时也降低了高优先级业务的网络拥塞概率。     

A sustainable heuristic QoS routing algorithm for pervasive multi-layered satellite wireless networks

Due to the recent developments in wireless technology and electronics, it is feasible to develop pervasive algorithms for satellite environments. Multi-Layered Satellite Networks (MLSNs) that consist of low earth orbit and medium earth orbit satellites are becoming increasingly important since they have higher coverage and better service than single-layered satellite networks. One of the challenges in MLSNs is the development of specialized and efficient routing algorithms. In this paper, we improved the virtual topology strategy and import heuristic algorithm to satisfy the QoS requirements of the MLSN users. The QoS requirements include end to end delay; link utilization, bandwidth, and package loss rate are mainly focused in this paper. To satisfy the QoS requirements is a multi-parameter optimization problem, and it is convinced as a Non-deterministic Polynomial Complete problem already. As a solution, three typical heuristic algorithms—Ant Colony Algorithm, Taboo Search Algorithm and Genetic Algorithm are applied in the routing scheme in order to reduce package loss, link congestion and call blocking. Simulation results show that heuristic routing algorithm can provide more QoS guarantees than shortest path first algorithm on package loss rate, link congestion and call blocking.     

一种基于QoS的空间延迟/中断容忍网络拥塞控制方法

为缓解网络拥塞对空间延迟/中断容忍网络产生的影响,该文提出一种基于QoS的网络拥塞控制算法。该算法包括接触拥塞判断和基于QoS的数据转发两种机制,分别从接触剩余可用容量和节点剩余存储空间两方面对每一段接触的拥塞程度进行预测,将接触划分为不同的拥塞等级。在计算路由时,以整段路径中所包含接触的最高拥塞等级为该路径的拥塞等级,并根据该拥塞等级发送不同优先级的数据。实验表明,基于QoS的拥塞控制算法可以提高低优先级数据的传递率并在节点存储空间不足时降低最高优先级数据的传递时延。     

一种基于时延信息的多QoS快速自适应路由算法

本文在分析现有自适应蚁群算法局限性的基础上，提出了一种基于时延的自适应多QoS路由算法，它在满足带宽和时延波动约束条件下，直接利用前一周期的时延信息来更新路由表，以作为当前寻找路径的依据。仿真和分析结果表明，该算法具有快速准确的特点，能够及时协调网络拥塞和资源有效利用两者间的矛盾。     

基于改进蚂蚁算法的QoS路由算法的仿真研究

在研究传统蚂蚁算法的优缺点及其仿真实现的基础上,提出一种基于改进蚂蚁算法的QoS路由算法及其仿真方法.从算法的仿真实现角度对改进蚂蚁算法进行探讨.算法理论分析和仿真实验,表明改进蚂蚁算法达到了设计目的,具有思路直观、算法收敛快、拥塞应对能力强的优点.     

ECBRP: An Efficient Cluster-Based Routing Protocol for Real-Time Multimedia Streaming in MANETs

The dynamic characteristics of wireless networks and stringent QoS requirements of multimedia applications identify significant challenges for providing QoS guarantees for real-time multimedia streaming in such wireless environment. QoS routing protocols can decisively contribute to the QoS provision of network systems. This paper proposes an efficient cluster-based routing protocol (ECBRP) for real-time multimedia streaming in mobile ad hoc networks. First, to improve the stability of clusterheads, we introduce a new algorithm of cluster formation, in consideration of the node mobility and connectivity. Second, a link-broken detection mechanism is designed, which is able to distinguish whether packet loss is due to mobility or congestion, and to make proper reaction. This mechanism contributes to reduce route overhead, and to increase the decodable ratio of video frame at the application layer as well. Third, the routing protocol is enhanced via an adaptive packet salvage strategy, in order to alleviate the congestion in consideration of the characteristics of multimedia traffic. Our simulation experiment results demonstrate that the ECBRP leads to more stable cluster formation than the CBRP, and 80% decreases in the frequency of clusterhead changes against CBRP. As a result, the quality of real-time multimedia streaming is improved significantly, in terms of decodable frame ratio, delay and delay jitter, etc.     

A DISTRIBUTED QOS ROUTING BASED ON ANT ALGORITHM FOR LEO SATELLITE NETWORK

Low Earth Orbit (LEO) satellites provide short round-trip delays and are becoming in- creasingly important. One of the challenges in LEO satellite networks is the development of specialized and efficient routing algorithms. To satisfy the QoS requirements of multimedia applications, satellite routing protocols should consider handovers and minimize their effect on the active connections. A distributed QoS routing scheme based on heuristic ant algorithm is proposed for satisfying delay bound and avoiding link congestion. Simulation results show that the call blocking probabilities of this al- gorithm are less than that of Shortest Path First (SPF) with different delay bound.     

Analysis of Distributed DDQ for QoS Router

In a packet switching network, congestion is unavoidable and affects the quality of real‐time traffic with such problems as delay and packet loss. Packet fair queuing (PFQ) algorithms are well‐known solutions for quality‐of‐service (QoS) guarantee by packet scheduling. Our approach is different from previous algorithms in that it uses hardware time achieved by sampling a counter triggered by a periodic clock signal. This clock signal can be provided to all the modules of a routing system to get synchronization. In this architecture, a variant of the PFQ algorithm, called digitized delay queuing (DDQ), can be distributed on many line interface modules. We derive the delay bounds in a single processor system and in a distributed architecture. The definition of traffic contribution improves the simplicity of the mathematical models. The effect of different time between modules in a distributed architecture is the key idea for understanding the delay behavior of a routing system. The number of bins required for the DDQ algorithm is also derived to make the system configuration clear. The analytical models developed in this paper form the basis of improvement and application to a combined input and output queuing (CIOQ) router architecture for a higher speed QoS network.     

一种非精确状态下满足多QoS约束的 动态组播路由算法

提出了一种非精确状态下满足多QoS约束的动态组播路由算法——DMIQ,该算法采用改进的BF算法作为路径搜索算法,WFQ作为分组调度机制,链路延迟不确定且服从均匀分布,能在非精确状态且满足带宽、延迟抖动和丢包率约束的前提下确定具有最小跳数和开销的动态组播路由.仿真实验表明,DMIQ能在非精确状态且满足多QoS约束的前提下建立动态组播路由,在路由请求平均成功率、平均延迟和平均跳数等衡量指标下表现出良好的性能.