基于贪心嵌入的几何路由可扩展问题研究

几何路由只需局部路由信息即可实现路由全局可达,被认为具备良好的可扩展潜力,成为可扩展路由理论研究的重要方向之一.然而,几何路由的研究仍不成熟,其自身仍面临其他可扩展问题挑战,主要表现在3方面:贪心嵌入简洁性、路由路径延展度以及动态拓扑下坐标更新等.本文针对3方面的挑战分别综述现有的研究进展,给出各方案的优缺点,并指出未来主要的研究方向.     

可信路由机理及关键技术

文章认为由于网络规模的增大以及节点移动、多宿主、网络流量工程等需求的不断增强,使得路由可扩展性、安全性、可靠性等问题凸显。尽管与可信路由相对应的理论技术方案不断提出,但未能从根本上解决网络路由的可信任问题。为此文章提出可信路由体系结构模型、可信域内路由、可信域间路由等新网络环境下的可信路由参考机制,并对可信路由涉及的关键技术,如映射可扩展技术、路由信任机制、多径路由技术、服务质量保证、路由监测管理技术,进行了研究和探讨。     

复杂网络与可扩展路由

互联网规模扩大,相应路由表大小呈指数增加,形成下一代互联网可扩展路由“瓶颈”。基于复杂网络和可扩展路由的相关理论与主要策略,文章对相关研究成果。如小世界效应所表现出来的特性、小世界和无标度网络模型,网格、层次及隐藏度量等3种可扩展路由网络模型,随机游走、贪婪、最大度、优先、本地介数、距离与度及相似性与度混合等多种路由策略等进行了分析与归纳。这些研究结果和方法为因互联网规模不断扩大所带来的路由系统可扩展性问题提供解决方案     

基于多项服务质量的域间路由方案

针对广域网中节点数量多,范围广的特点,提出了一种将节点划分成域,并以带宽、时延作为服务质量（ＱｏＳ）指标在域间寻找可行路径的路由方案。该方案由两个算法组成,它们在把真实网络映射成为具有分级结构图的同时给出了满足服务质量要求的可行路径。     

用于Ad Hoc网络的多径混合路由

移动Ad hoc网络是由一组移动节点组成的临时网络,它不需要事先建立的网络基础设施的支持。路由协议对网络性能起着决定性的作用。文中提出了一种基于多路径的Ad hoc网络混合路由策略（MPHR）。在MPHR中,边权值表示节点之间的链路可靠性。与传统的单路径路由策略不同,在一对源节点和目的节点间,使用多条路径来发送分组。仿真结果表明,MPHR的分组投递率远高于DSR路由协议,但路由开销略大于DSR。     

一种新的应用层对等路由机制的研究

提出了一种基于对等网的路由方案.该方案首先在网络中部署多个服务器,每个服务器维护一个连接其他服务器的时延二叉树,每个动态节点归属于某个服务器管辖.基于该树,任何两个动态节点能够以较小的代价快速建立通信所需的路由路径.仿真测试结果证明了这一方案具有较好的性能.     

MPLS网络中的QoS路由粒度研究

研究了基于约束的路由决策粒度对MPLS网络中QoS路由可靠性和阻塞性能的影响。为实现成本效益的可测量性,这里在现有粒度方案的基础上,提出了使用混合粒度方案：每对/流粒度方案和每对/类粒度方案。有每对/流粒度的每对流方案增加了P缓存和O缓存作为路由缓冲,完成了低阻塞率。有每对/类粒度的每对类方案将流汇聚到几条路由路径,从而允许数据包在有限的缓存规模内被标签转发。仿真结果表明,混合粒度方案减少了路由缓存规模,适合于MPLS网络。     

基于灰色关联的ZigBee网络混合路由算法

ZigBee网络混合路由算法(ZigBee Routing,ZBR)中将源节点和目的节点之间的最小跳数作为唯一的路由度量因素.但随着节点能量消耗以及节点的频繁移动,ZBR算法的这一特性会造成网络间歇性连接,从而导致网络性能下降.提出一种选择最优分组转发路径的ZigBee网络混合路由算法(Grey Relational Algorithm based ZBR,GRA-ZBR).GRA-ZBR算法在目的节点选择路径时引入灰色关联算法,综合考虑节点剩余能量、链路质量、节点剩余队列长度以及路径长度等因素.仿真结果表明,GRA-ZBR算法可以有效提高网络分组投递率,降低平均端到端时延.     

MR2-GRADE:一种基于梯度值的无线传感器网络高能效多径干扰避免路由协议

无线传感器网络的径间干扰是多径路由亟待解决的重要问题,然而目前干扰避免策略的设计忽略了无线传感器网络最关心的能耗问题.本文提出基于梯度的MR2-GRADE路由协议框架,利用已建路径上各节点到目的节点的跳数构造干扰范围外节点的网络梯度,有效避免传统广播方式的高路由开销.针对基于梯度的局部路由决策导致后续路径创建成功率受网络节点分布密度影响较大的问题,设计了基于梯度的贪婪转发算法GRADE_GF和受限泛洪算法GRADE_RF.仿真实验结果表明:与已有的同类多径干扰避免路由相比,基于MR2-GRADE协议框架的路由可有效降低路由开销,随着网络规模扩大,优势越明显.     

认知无线电网络层路由问题研究

在认知无线电中,网络层用于确定如何在网络中找到一条从源节点到目标节点的路径,且数据路径应当是适应频谱状况的,即尽可能绕过主用户频繁出现的区域。由于频谱是随机的,因而数据路径也可能是随机的。文章分析认知无线电网络中路由面临的挑战,介绍认知无线电网络中的两种路由方案:静态路由和动态路由,给出静态路由频谱选择阶段的5个指标,研究静态路由下一跳选择阶段的优化问题,最后提出认知无线电网络动态路由的实现方案。     

基于名的平坦路由

路由是信息网络的基础,分布于网络的各个层面。现有互联网采用了基于IP地址的网络层路由技术和基于域名解析的域名服务器（DNS）应用层路由技术。由于IP地址和域名的结构化特点和身份位置紧耦合特点,使得互联网面临路由可扩展性、安全性、资源服务迁徙移动支持性差等严峻问题。基于名的平坦路由采用了平面化的身份命名方式,实现了身份位置分离,可有效提高网络路由的可扩展性、可配置性、安全性、服务支持的鲁棒性、资源移动的支持性等。     

基于表面自适应的定向贪婪选路

针对无线传感器网络中基于位置的路由算法中存在的重复搜索和冗余计算问题,提出一种基于表面自适应的定向贪婪路由算法（DGAFR）。该算法充分发挥贪婪转发、表面路由转发和定向选路的优势,依据局部区域节点的状态信息进行整个网络的路由选择。理论上分析证明DGAFR算法具备渐近最优性;仿真结果表明,相比于GPSR和GOAFR,该算法降低了大量额外的通信和计算开销,更适于大型的传感器网络。     

Safari: A self-organizing, hierarchical architecture for scalable ad hoc networking

As wireless devices become more pervasive, mobile ad hoc networks are gaining importance, motivating the development of highly scalable ad hoc networking techniques. In this paper, we give an overview of the Safari architecture for highly scalable ad hoc network routing, and we present the design and evaluation of a specific realization of the Safari architecture, which we call Masai. We focus in this work on the scalability of learning and maintaining the routing state necessary for a large ad hoc network. The Safari architecture provides scalable ad hoc network routing, the seamless integration of infrastructure networks when and where they are available, and the support of self-organizing, decentralized network applications. Safari’s architecture is based on (1) a self-organizing network hierarchy that recursively groups participating nodes into an adaptive, locality-based hierarchy of cells; (2) a routing protocol that uses a hybrid of proactive and reactive routing information in the cells and scales to much larger numbers of nodes than previous ad hoc network routing protocols; and (3) a distributed hash table grounded in the network hierarchy, which supports decentralized network services on top of Safari. We evaluate the Masai realization of the Safari architecture through analysis and simulations, under varying network sizes, fraction of mobile nodes, and offered traffic loads. Compared to both the DSR and the L+ routing protocols, our results show that the Masai realization of the Safari architecture is significantly more scalable, with much higher packet delivery ratio and lower overhead.     

QoS路由度量参数的选择问题研究

具有服务质量保证的QoS路由技术是为具有QoS要求的多媒体等网络业务提供有保证的网络服务的核心要素。QoS路由技术由路由选择算法以及用于反映网络状态的路由度量参数的选择、获取与更新两部分内容组成。正确选取合适的度量参数是减小寻路开销，得到简单、具有扩展性的选路算法并获得满足业务要求的QoS路由的前提与基础。本对QoS路由所需要的度量参数的基本性质、选取方法等问题进行了较全面的分析讨论，并简要介绍了度量信息更新的基本策略。     

VANETs路由协议的研究进展

车辆自组织网络是传统自组织网络派生出的一个分支,其与应用场景高度相关.传统路由协议不能有效的适用于车辆自组织网络,因此,针对车辆自组织网络提出了许多新的路由协议.首先在总结车辆自组织网络的特性后,分别介绍了单播路由、广播路由和地域性多播路由的概念,然后着重分析和总结了近年来具有代表性的路由协议的核心路由机制及其优缺点,...     

ASON路由技术及其进展

文章对国际上各个标准组织，如ITU-T、IETF和OIF，在自动交换光网络(ASON)路由技术方面的进展情况进行了介绍，包括标准制订工作流程和互通演示测试等方面；对传送网的分层结构和ASON的分级路由之同的关系进行了讨论，认为ASON应该支持多级路由方式，允许运营商根据需要组织网络结构，这对于ASON网络的规划和建设具有一定的参考意义。     

Power-aware single- and multipath geographic routing in sensor networks

Nodes in a sensor network, operating on power limited batteries, must save power to minimize the need for battery replacement. We note that the range of transmission has a significant effect on the power consumption of both the transmitting node and listeners. This paper first presents a Geographical Power Efficient Routing (GPER) protocol for sensor networks. Each sensor node makes local decisions as to how far to transmit: therefore, the protocol is power efficient, localized, highly distributed, and scalable. In GPER, given a final destination, each node first establishes a subdestination within its maximum radio range. The node, however, may decide to relay the packet to this subdestination through an intermediary node or alter the subdestination if this will preserve power. Traditional deterministic geographic routing algorithms aim at achieving close to the shortest weighted paths. However, they normally stick to the same paths for the same source/destination pairs. This may conversely drain the nodes on these paths and result in short network life when the communication in the network is unevenly distributed. Thus, we further investigate a set of probabilistic multipath routing algorithms, which generate braided multipaths based only on local information. The algorithms have less communication and storage overhead than conventional on-demand multipath routing algorithms, while providing greater resilience to node failures. Simulations on NS2 show that GPER almost halves the power consumption in the network relative to alternative geographic routing algorithms. Furthermore, in situations where the communication tasks are non-uniformly distributed, probabilistic multipath routing contributes up to an additional 30% to network lifetime.     

互联网BGP路由可视及安全检测技术架构与实践

边界网关协议（border gateway protocol,BGP）是支撑互联网50年来快速发展的核心协议,因早期设计考虑不足一直存在路由劫持、路由泄露等路由安全威胁漏洞。随着互联网应用日益深入,BGP 路由安全问题逐渐引起业界重视,边界网络安全防护意义重大。提出了一种BGP路由安全检测架构,通过推理构建全球BGP路由知识库实现互联网全局路由可视性,并基于此实现路由劫持、路由泄露等路由安全事件的准实时检测。通过在杭州交换中心部署实践,证明本系统可构造较完整的互联网全局路由知识库、实现较准确和实时的BGP路由安全事件检测。     

SIAR: Customized real-time interactive router for analog circuits

As analog and mixed-signal (AMS) circuitry gains increasing portions in modern SoCs, automatic analog routing is becoming more and more important. However, routing for analog circuits has always been an extremely challenging task due to complicated electrical and geometrical constraints. Due to these constraints, current analog routers often fail to obtain a routing solution that the designer wants. To incorporate the designer׳s expertise during routing, a customized real-time interactive analog router is attracting increasing concerns in industry.This paper presents a fast customized real-time interactive analog router called SIAR. A key feature of SIAR is that it allows for real-time interactions between the router and the designer. The designer can try different guiding points by moving the cursor in the user window and SIAR will return and display the corresponding routing solution in real-time, such that the designer could choose the most satisfactory one. The guiding points are very important for the designer to obtain satisfactory routing solutions, even for routing solutions with analog matching constraints by setting symmetric guiding points. A new splitting graph based routing model is presented to efficiently search the routing path and record the number of turns/vias during searching by efficient tile splitting operations. SIAR supports different routing modes such as point-to-point, point-to-module and module-to-module. An efficient connecting point selection method is presented such that an optimal routing solution is preserved when connecting to a module. Different design rules such as variable wire and via width/spacing rules, along with the same-net spacing rules, are supported in SIAR. Moreover, a global routing stage is presented to speedup the routing process for large designs. Experimental results are promising.