基于AP算法的Internet自治系统层紧凑路由研究

提出了一种基于AP算法的Internet自治系统层紧凑路由算法.用r近邻的负距离表示节点对的相似度,得到网络的相似度矩阵.基于相似度矩阵,利用AP算法对网络进行划分,得到每个聚类簇的基点.在聚类后的网络上进行紧凑路由.通过对Internet自治系统层网络拓扑数据进行大量实验,确定了AP算法中偏好参数的取值范围,并分析了...     

IP/WDM网络中的链路保护路由算法研究

基于IP/WDM网络的对等模型,在联合路由的基础上,对SRLG约束的联合共享链路保护机制的路由选择与资源分配算法进行了研究,并提出了一种新的MI-APF-ISLP算法.为了验证该算法的有效性,以自相似和Poisson模型两种业务模型为基础,将连接阻塞概率CBP和带宽吞吐率BTP作为性能指标,在不同参数条件下进行动态仿真,结果表明MI-APF-ISLP算法要优于传统算法.     

自相似业务在WDM环网中的动态性能分析

对自相似业务在WDM环网中的动态路由波长分配(RMA)问题进行了研究,以16节点格环网为例对自相似业务在不同波长路由分配策略下的动态性能进行了仿真。分析了单纤和多纤环境下阻塞率随自相似突发度H变化的规律。同时又以性能差异比例函数为依据,比较了不同路由算法间阻塞率的差异,并与相同条件下的泊松模型进行了对比。     

基于自相似业务的移动Ad hoc网络路由算法研究

该文分析了移动Adhoc网络中普遍存在但被忽视的自相似业务的路由和排队性能,提出了基于网络规划模型的多径备份路由优化功率(MBOP)算法。该算法利用多路径和备份路由,并对网络的发射功率进行优化,适用于网络结构动态变化的移动无线自组织网络。仿真结果表明,该算法可以显著改善节点的排队性能,提高网络的吞吐量改进时延性能。     

一种基于流内与流间网络编码的无线路由算法

 网络编码能极大提高网络吞吐量和可靠性.该文提出了一种基于流内网络编码与流间网络编码的无线路由算法,首先用改进的流间网络编码策略寻找一条固定路由,发现尽可能多的编码机会以减少传输次数;再用流内网络编码与局部机会路由结合的方法实施每跳的数据包传输,减少数据包的重传次数.理论分析和仿真实验表明,此算法比传统的编码感知路由算法具有更高的吞吐量和可靠性.     

基于时间槽的自相似流量随机早检测算法——SFRED

分析研究了网络流量的自相似和长相关性,并基于分形布朗运动模型导出了自相似流量环境RED算法分组丢失概率的一种计算方法,从而提出了基于时间槽的自相似流量随机早检测队列管理算法SFRED.该算法在每个时间槽内计算一次分组丢失概率,大大降低系统负担.NS2仿真实验表明SFRED算法性能明显优于RED,能够很好地在自适应流背景下控制队列长度,并具有良好的吞吐量性能.     

基于ON/OFF源模型的OBS汇聚算法研究

近年来,大量研究表明,网络业务流量呈现长相关、自相似的特性,采用ON/OFF源模型生成自相似流能够比较真实地反映现实网络中的业务流量。光突发包的汇聚算法是光突发交换的关键技术之一,利用ON/OFF模型生成的自相似流对几种典型的OBS汇聚算法进行研究。仿真表明,不同算法对自相似的影响不同。     

基于位置信息的自组织网络路由算法研究

定位技术的快速发展使得获取位置信息的成本越来越低,此外利用位置信息可以有效降低路由开销,因此,基于位置信息的路由算法逐渐成为自组织网络路由算法的热点。在对现有基于位置信息的路由算法进行分析的基础上,对单播路由算法中贪婪转发算法及空洞处理算法进行研究,并对基于位置信息的多播路由算法及地理区域路由算法作了简要概述。     

基于主动网络的多约束路由探测算法

本文提出了一种基于主动网络的多约束路由探测算法MAR(Multi-constrained Active Routing).与传统路由算法相比,MAR不仅能灵活地提供多种约束条件的服务质量保证,而且充分发挥了主动网络的可编程和自定制能力,允许用户根据业务要求和网络状况自定制约束条件和相关参数.通过仿真MAR算法在各种网络条件下的性能表明,MAR算法能够提高多约束条件寻路的成功率.     

移动自组织网络基于链路稳定性的伪流言路由算法

分析了移动自组织网络中链路和路径的有效性的统计特性,并结合流言机制提出了一种基于链路稳定性的伪流言路由算法.该路由算法可以用更少的路由开销发现持续更长时间的稳定路由.仿真实验表明该算法与AODV结合显著地提高了网络的性能.     

On multimedia networks: self-similar traffic and networkperformance

The main objective in telecommunications network engineering is to have as many happy users as possible. In other words, the network engineer has to resolve the trade-off between capacity and QoS requirements. Accurate modeling of the offered traffic load is the first step in optimizing resource allocation algorithms such that provision of services complies with the QoS constraints while maintaining maximum capacity. As broadband multimedia services became popular, they necessitated new traffic models with self-similar characteristics. We present a survey of the self-similarity phenomenon observed in multimedia traffic and its implications on network performance. Our current research aims to fill the gap between this new traffic model and network engineering. An immediate consequence of this study is the demonstration of the limitations or validity of conventional resource allocation methods in the presence of self-similar traffic     

Making Routing Robust to Changing Traffic Demands: Algorithms and Evaluation

Intra-domain traffic engineering can significantly enhance the performance of large IP backbone networks. Two important components of traffic engineering are understanding the traffic demands and configuring the routing protocols. These two components are inter-linked, as it is widely believed that an accurate view of traffic is important for optimizing the configuration of routing protocols, and through that, the utilization of the network. This basic premise, however, seems never to have been quantified. How important is accurate knowledge of traffic demands for obtaining good utilization of the network? Since traffic demand values are dynamic and illusive, is it possible to obtain a routing that is "robust" to variations in demands? We develop novel algorithms for constructing optimal robust routings and for evaluating the performance of any given routing on loosely constrained rich sets of traffic demands. Armed with these algorithms we explore these questions on a diverse collection of ISP networks. We arrive at a surprising conclusion: it is possible to obtain a robust routing that guarantees a nearly optimal utilization with a fairly limited knowledge of the applicable traffic demands     

A survey and analysis of multipath routing protocols in wireless multimedia sensor networks

The main objective of this research is to conduct a performance analysis of various multipath routing protocols in wireless multimedia sensor networks for the efficient transmission of the image, audio and video data. To provide efficient routing for the large sized multimedia content, various multipath routing protocols such as energy-aware routing, QoS based routing and geographical routing methods are analyzed. In this analysis, the efficient routing techniques including geographical routing techniques such as GPSR, DGR, PW-DGR presented for wireless multimedia sensor networks are studied and the performance of each technique is evaluated to determine the efficient multipath routing technique. Comparisons are made for evaluated protocols and it is proved that the PW-DGR provides better routing performance for the multimedia data. The findings of the research also show that the PW-DGR method efficiently overcomes the routing problems such as energy bottleneck problem, energy-hole, reduced network lifetime and high delay in packet transmission.     

A simulation study of table-driven and on-demand routing protocolsfor mobile ad hoc networks

Bandwidth and power constraints are the main concerns in current wireless networks because multihop ad hoc mobile wireless networks rely on each node in the network to act as a router and packet forwarder. This dependency places bandwidth, power, and computation demands on mobile hosts which must be taken into account when choosing the best routing protocol. In previous years, protocols that build routes based on demand have been proposed. The major goal of on-demand routing protocols is to minimize control traffic overhead. We perform a simulation and performance study on some routing protocols for ad hoc networks. The distributed Bellman-Ford (1957, 1962), a traditional table-driven routing algorithm, is simulated to evaluate its performance in multihop wireless network. In addition, two on-demand routing protocols (dynamic source routing and associativity-based routing) with distinctive route selection algorithms are simulated in a common environment to quantitatively measure and contrast their performance. The final selection of an appropriate protocol will depend on a variety of factors, which are discussed in this article     

Traffic engineering with traditional IP routing protocols

Traffic engineering involves adapting the routing of traffic to network conditions, with the joint goals of good user performance and efficient use of network resources. We describe an approach to intradomain traffic engineering that works within the existing deployed base of interior gateway protocols, such as Open Shortest Path First and Intermediate System-Intermediate System. We explain how to adapt the configuration of link weights, based on a networkwide view of the traffic and topology within a domain. In addition, we summarize the results of several studies of techniques for optimizing OSPF/IS-IS weights to the prevailing traffic. The article argues that traditional shortest path routing protocols are surprisingly effective for engineering the flow of traffic in large IP networks.     

WDM对终端业务和高层协议的影响

主要从基于 WDM网络的网络层及其高层出发 ,描述了以下问题 :业务准备算法以便最小化电复用的代价 ;波长分配算法 ;光层和电层联合保护和恢复 ;光网络拓扑对高层协议 ,如 IP选路、TCP流量控制和多层交换对光网络拓扑的影响。     

A QoS Routing Protocol with Bandwidth Allocation in Multichannel Ad Hoc Networks

Mobile multimedia applications have recently generated much interest in mobile ad hoc networks (MANETs) supporting quality-of-service (QoS) communications. Multiple non-interfering channels are available in 802.11 and 802.15 based wireless networks. Capacity of such channels can be combined to achieve higher QoS performance than for single channel networks. The capacity of MANETs can be substantially increased by equipping each network node with multiple interfaces that can operate on multiple non-overlapping channels. However, new scheduling, channel assignment, and routing protocols are required to utilize the increased bandwidth in multichannel MANETs. In this paper, we propose an on-demand routing protocol M-QoS-AODV in multichannel MANETs that incorporates a distributed channel assignment scheme and routing discovery process to support multimedia communication and to satisfy QoS bandwidth requirement. The proposed channel assignment scheme can efficiently express the channel usage and interference information within a certain range, which reduces interference and enhances channel reuse rate. This cross-layer design approach can significantly improve the performance of multichannel MANETs over existing routing algorithms. Simulation results show that the proposed M-QoS-AODV protocol can effectively increase throughput and reduce delay, as compared to AODV and M-AODV-R protocols.     

多媒体通信中的多点路由问题

多点通信是网络支持多媒体业务的关键技术之一。本文在不同优化选路准则下,结合当前应用背景介绍了基于最短路径和共享树的多点路由算法及其应用环境和性能分析,在此基础上对有关协议进行了讨论,最后结合多媒体业务的特征分析了多点路由算法的几个发展方向,以期对多点通信的路由问题最近和将来的研究给出必要的背景。     

GeoDTN<Emphasis Type="Bold">+</Emphasis>Nav: Geographic DTN Routing with Navigator Prediction for Urban Vehicular Environments

Position-based routing has proven to be well suited for highly dynamic environment such as Vehicular Ad Hoc Networks (VANET) due to its simplicity. Greedy Perimeter Stateless Routing (GPSR) and Greedy Perimeter Coordinator Routing (GPCR) both use greedy algorithms to forward packets by selecting relays with the best progress towards the destination or use a recovery mode in case such solutions fail. These protocols could forward packets efficiently given that the underlying network is fully connected. However, the dynamic nature of vehicular network, such as vehicle density, traffic pattern, and radio obstacles could create unconnected networks partitions. To this end, we propose GeoDTN+Nav, a hybrid geographic routing solution enhancing the standard greedy and recovery modes exploiting the vehicular mobility and on-board vehicular navigation systems to efficiently deliver packets even in partitioned networks. GeoDTN+Nav outperforms standard geographic routing protocols such as GPSR and GPCR because it is able to estimate network partitions and then improves partitions reachability by using a store-carry-forward procedure when necessary. We propose a virtual navigation interface (VNI) to provide generalized route information to optimize such forwarding procedure. We finally evaluate the benefit of our approach first analytically and then with simulations. By using delay tolerant forwarding in sparse networks, GeoDTN+Nav greatly increases the packet delivery ratio of geographic routing protocols and provides comparable routing delay to benchmark DTN algorithms.     

FIRE: flexible intra-AS routing environment

Current routing protocols are monolithic, specifying the algorithm used to construct forwarding tables, the metric used by the algorithm (generally some form of hop count), and the protocol used to distribute these metrics as an integrated package. The flexible intra-AS routing environment (FIRE) is a link-state, intradomain routing protocol that decouples these components. FIRE supports run-time-programmable algorithms and metrics over a secure link-state distribution protocol. By allowing the network operator to dynamically reprogram both the properties being advertised and the routing algorithms used to construct forwarding tables, FIRE enables the development and deployment of novel routing algorithms without the need for a new protocol to distribute state. FIRE supports multiple concurrent routing algorithms and metrics, each constructing separate forwarding tables. By using operator-specified packet filters, separate classes of traffic may be routed using completely different routing algorithms, all supported by a single routing protocol. This paper presents an overview of FIRE, focusing particularly on FIRE's novel aspects with respect to traditional routing protocols. We consider deploying several current unicast and multicast routing algorithms in FIRE, and describe our Java-based implementation