区分自治系统关系的域间路由体系研究

BGP-4是Internet采用的惟一域间路由协议，但它并不能确保路由收敛，复杂的网络结构加剧了路由潜在振荡的危险性．为此，提出了一种自约束的域间选路机制，在不违反传统流量工程原则和自治系统间结算原则的前提下，通过抑制违背自治系统间关系的路由通告和路由选择，达到维护全系统路由稳定的目的；对昕提方案的技术可行性进行论证，给出了新的选路机制原型系统的定义和关键算法的实现．区分自治系统关系的域间路由体系有效回避了路由策略一致性全局检测这一NP-complete问题．     

边界网关协议BGP4路由收敛问题研究进展

边界网关协议BGP4是目前Internet最主要的域问路由协议，其路由正确性和稳定性直接关系到Internet能否正常运行．作为一个域问路由协议，BGP协议必须支持策略路由，允许各个自治系统独立的制定他们的路由策略，而且允许这些策略优先于路径尺度．由于各个自治系统制定策略的角度不同，这些路由策略之间可能存在冲突，从而导致BGP协议发散及路由振荡．此外，BGP协议本身也存在一些内在机制的不完善，并可能导致在某些情况下路由不收敛或收敛速度缓慢．随着网络规模越来越大，拓扑越来越复杂，BGP路由收敛问题日趋严重，目前国内外对此展开了大量的研究，并提出了多种分析模型和解决方案．本文首先全面总结了BGP协议面临的主要的收敛问题，主要包括策略冲突和协议机制造成的不收敛问题和收敛缓慢问题，然后全面介绍了针对这些问题的现有的解决方案，分析比较了这些方案的优点和缺点，最后提出了进一步的研究设想．     

自治域生态系统的对等连接行为分析

传统网络行为分析忽视了自治域的经济特性对网络结构产生的影响。从成本收益的角度分析了不同类型自治域的对等连接行为。通过PeeringDB提供的样本数据，首先统计域间流量分布情况，给出不同类型自治域的对等连接偏好。结果表明，传输服务提供商和接入服务提供商的域间流量与对等连接策略之间存在较强的关联，而内容服务提供商的域间流量与对等连接策略的关联性较弱，主要采取开放式对等连接。根据服务提供商在信息流传输中的作用，分析了经济环境下自治域采取对等连接策略的主要原因，提出自治域是由网络结构、域间流量和成本收益相互影响的生态系统。     

MPLS流量工程的内部网关协议

围绕MPLS流量工程的内部网关协议问题进行讨论，文章首先介绍传统的Internet流量工程内部网关协议，再介绍目前流量工程的约束路由，约束路由的特征，分析了现有增强内部网关协议（EIGP）对MPLS流量工程的支持，最后作者根据EIGP的一些问题，提出了一套改进方案。     

一种基于BT 的域间P2P 流量优化方法

随着P2P软件的普及,P2P成为影响Internet网络结构的关键应用．在中国运营商的长途骨干网上,P2P流量占一半以上,不仅给ISP带来了巨大的压力,也使网络拥塞现象日益严重．据此本文以P2P常用协议BT为对象提出一种优化方案,通过用户协作与估算模拟底层网络相综合的方法,在不影响性能下,引导流量更多地在本地网络上发生,降低域间及主干网络上的P2P流量．测试表明,该机制不仅能尽量将域间流量本地化达到整体优化的目的。而且更能增强用户系统的性能．     

域间路由策略的协同管理问题

互联网由多个自治域互联组成,自治域之间按照各自的域间路由策略交换路由信息和转发流量。由于管理自治域的ISP各自为政,独立配置和管理自己的路由策略,缺少协同机制,容易引起路由震荡、热土豆路由、异常路由等问题。本文提倡采用协同的方式管理域间路由策略,通过列举一些典型的域间路由策略问题,提出一套域间路由策略的多方协同控制与管理体系,并重点讨论了协同管理的基础性问题--安全比较协议。该协议可以被应用在互联网域间路由策略的管理中,对于分布式故障检测、分布式网络性能能测量等相关应用,也具有较好的参考价值。     

基于Internet的远程控制系统研究

在介绍目前国际上基于Internet的远程控制系统研究现状的基础上，讨论网络远程控制体系的结构组成．分析了控制与观测过程中网络不确定性时延对系统稳定性的影响，提出状态空间的描述方法与基于S域输入输出模型以及相应的时延补偿策略。     

MPLS网络流量工程的关键机制剖析

1 引言随着Internet的蓬勃发展,网络中新技术、新业务层出不穷,Internet已从单一的数据传送网逐步演化成为综合业务网。网络业务的多元化导致了对网络需求的复杂化,要求网络提供高效、可靠的服务,能够保证服务质量,这对网络流量工程技术提出了极大的挑战,人们迫切需要一种有效且切实可行的解决方案。 MPLS在无连接的网络中提供了面向连接的特性,使MPLS在实施流量工程方面有明显的优势。目前,大多数的流量工程解决方案都采用MPLS作为转发机制。许多研究人员     

互联网的局域世界演化模型仿真研究

研究Internet拓扑有利于解决Internet上通信协议、病毒传播、拥塞控制等问题，针对不同的预测和改善Internet性能的目的，建立合适的拓扑模型是非常重要的。该文从复杂网络建模的角度出发，研究了自治系统层面Internet的拓扑特性，综合考虑了局域世界内的偏好连接、节点和链接的随机或优先消亡、节点间非线性优先连接、新节点所带来的外部链接及网络内新增的内部链接等诸多因素，提出了一个新的Internet局域世界演化模型ELWI。采用C＋＋和Matlab这两个工具来对Internet和所生成的ELWI拓扑进行研究，通过比较仿真结果发现，ELWI很好地刻画了自治系统层面Internet的无标度、小世界和局域世界等诸多特性及其演化行为。     

互联网自治域商业关系推测算法

随着互联网进入商业化发展阶段,不同管理机构的自治域通过商业合作关系来共同路由互联网中的流量.从工程上来看,获取全面准确的自治域商业关系可以指导有效的流量工程管理和资源部署从而均衡网络负载,提高服务可靠性,减少网络运营成本;从理论上来看,获取全面准确的自治域关系可以分析互联网的演进模型,指导设计新的路由协议和互联网架构.虽然互联网路由注册中心会记录自治域之间的商业关系,但是由于商业敏感以及注册中心缺乏维护更新,公开的自治域商业关系并不全面准确,因而通过推测算法获得更加全面准确的自治域商业关系成为了学术界与产业界关注的热点.文中系统地综述了现有的互联网自治域商业关系推测算法及其存在的问题,并对该领域有待进一步研究的问题和可能的解决方案给出了一些建议.     

CoreCast: How core/edge separation can help improving inter-domain live streaming

The rapid growth of broadband access has popularized multimedia services, which nowadays contribute to a large part of Internet traffic. Among this content, the broadcasting of live events requires streaming from a single source to a large set of users. For such content, network-layer multicast is the most efficient solution, but it has not found wide-spread adoption due to its high deployment cost. As a result, several application-layer solutions have been proposed based on large-scale P2P systems. These solutions however, are unable to provide a satisfactory quality of experience to all users, mainly because of the variability of the peers and their limited upload capacity. In this paper we advocate for a network-layer solution that circumvents the prohibitive deployment costs of previous approaches, taking advantage of the rare window of opportunity offered by the locator/identifier separation protocol (LISP). This new architecture, motivated by the alarming growth rate of the default-free zone (DFZ) routing table, is developed within the IETF, and aims to upgrade the current inter-domain routing system. We present CoreCast, an efficient inter-domain live streaming architecture operating on top of LISP. LISP involves upgrading some Internet routers and our proposal can be introduced along with these new deployments. To evaluate its feasibility in terms of processing overhead in networking equipment we have implemented CoreCast in the Linux kernel. Further, we compare the performance of CoreCast to the popular P2P streaming services both analytically and experimentally. The results show that CoreCast reduces inter-domain bandwidth consumption and that introduces negligible processing overhead in network equipment.     

AdaptIDC: Adaptive inter-domain communication in virtualized environments

Owing to the isolation barrier between VMs, inter-domain communication suffers great performance loss. Current solutions widely exploit inter-domain shared memory mechanism to improve performance. Also the larger the shared memory buffer is, the higher the throughput and the less the latency. However, these solutions which use static fixed size shared memory, do not take memory utilization and the heterogeneous upper applications into consideration. In this paper, we have designed and implemented an adaptive shared memory mechanism for inter-domain communication, called AdaptIDC, adjusting the shared memory dynamically. With the help of completely independent in/out buffer design, the IOIHMD adjustment algorithm, the control ring and event channel reuse mechanism, AdaptIDC achieves superior shared memory utilization and yet does not sacrifice high performance between co-existing VMs. In the evaluation, we observe that AdaptIDC can greatly improve the shared memory utilization while performance draws near the fixed static shared page solution.     

Evolution of Inter-domain Traffic Engineering:Standards, Research and Current Applications

This paper briefly describes how inter-domain traffic engineering (TE) is evolving and how it can be used for effective commercial networking as well as for high performance networking in Asia and around the globe.     

Information aspects and future directions in an integrated telecommunications and enterprise management environment

Commercial enterprises are becoming increasingly involved with telecommunications as their use of networks increases. This has implications for corporate management systems as they are faced with integrating telecommunication management concepts into their local management systems. THis paper investigates the information aspects of the integrated management of telecommunications networks, services and systems, and the related databases for the purpose of corporate management. It distinguishes between management information required locally and information needed for inter-domain management. Two examples of research work being undertaken in this area are discussed and a strategy based on an integrated management information repository is introduced. The first project shows how management relevant information from different actors can be incorporated into an integrated interdomain management information base by using the TMN X interface, whereas the second example provides solutions for the integration of the heterogeneous information bases within one large enterprise. Both examples have been chosen to demonstrate that the migration to integrated management systems will require the use of standardized and comprehensive interfaces, such as the TMN X interface.     

一种自适应的ICN移动性机制

信息中心网络（information-centric networking,ICN）内在地支持兴趣请求者移动而不支持内容提供者移动,然而在实际的场景中往往发生的是内容提供者移动。当前的移动性解决方案存在一些缺憾,如没有真正地考虑移动设备的加入/离开、机制过于单一不能应对各种移动场景、网络切换时延过长等。为解决上述问题,面向区域划分设计一种自适应的移动性机制,包括基于汇聚点的域内移动解决方案、基于兴趣转发的域间移动解决方案和基于回溯的基站间移动解决方案。仿真在GTS网络拓扑上进行,实验结果表明所提的移动性机制较基准机制有高的分发率、低的切换时延和少的路由跳数,说明所提的移动性机制具有广泛的应用价值,为推动诸如5G应用的全面落地具有现实的意义。     

TMP-TIE:基于流量迁移预测的域间出口选择算法

出口选择算法是域间路由策略的直接体现,并具备流量工程能力。针对可调域间路由出口选择算法引起的大幅流量迁移问题,以控制与转发分离的网络架构为背景,提出了基于流量迁移预测的出口选择算法TMP-TIE。该算法在TIE算法的基础上加入对流量迁移的预测和判定,避免出口变化引起的大幅流量迁移,降低对域间流量传输的影响。通过模拟实验比较了热土豆、TIE和TMP-TIE的性能,实验结果说明,TMP-TIE具有最小的路由敏感性和流量敏感性,能降低故障条件下的网络代价和网络拥塞的概率,有利于实现域间流量工程。     

A Hybrid End-to-End QoS Path Computation Algorithm for PCE-Based Multi-Domain Networks

Inter-domain quality of service (QoS) routing is a challenging problem for today’s Internet. This problem requires the computation of paths that cross multiple domains and meet different QoS constraints. In addition, the used computation methods must meet the constraints of confidentiality and autonomy imposed by the domains of different operators. Path computation element (PCE)-based architecture offers a promising solution for inter-domain QoS routing. It ensures the computation of end-to-end QoS paths while preserving the confidentiality and the autonomy of the domains. In this paper, we propose a novel hybrid end-to-end QoS path computation algorithm, named HID-MCP, for PCE-based networks. HID-MCP is a hybrid algorithm that combines the advantages of pre-computation and on-demand computation to obtain end-to-end QoS paths. Moreover, it integrates a crankback mechanism for improving path computation results in a single domain or in multiple domains based on the PCE architecture. Detailed analyses are provided to assess the performance of our algorithm in terms of success rate and computational complexity. The simulation results show that our algorithm has an acceptance rate of the requests very close to the optimal solution; precisely, the difference is lower than 1 % in a realistic network. Moreover, HID-MCP has a low computational complexity. Besides, our solution relies on the PCE architecture to overcome the limitations related to inter-domain routing such as domain autonomy and confidentiality.     

A trust degree based access control in grid environments

The purpose of grid computing is to enable coordinated resource sharing and support cooperative work between different domains in dynamic grid environments. In order to protect each participant’s privilege and security, a secure and efficient access control is essential. This paper presents a new approach of access mechanism based on trust relationships across domains. A new calculation method of trust in grid is proposed and the difference between intro-domain trust and inter-domain trust is analyzed. In addition, a novel access control framework combined with trust degree is given from this proposal. It is shown to be adaptive for both intro-domain and inter-domain conditions. Hence, a prototype system based on the proposed model is introduced; furthermore, it has been shown as a dynamic and fine-granularity access control method through performance analyses and has also been demonstrated as a suitable system for grid environments.     

快速层次移动IPv6的域间移动管理

为了提升移动IPv6域间切换的性能,在FHMIPv6的机制上提出了一种基于边缘接入路由器的域间移动管理方案。在这种方式下,移动主机在移动到边缘接入路由器上时,进行域内切换并把链路转交地址在前移动锚点和新移动锚点上同时进行重复地址检测;完成切换后,在边缘接入路由器域内对新区域转交地址进行配置并在新MAP中与链路转交地址绑定。通过NS-2实验仿真验证能够有效减少域间切换带来的延迟,同时也降低了分组的丢失率。     

结合域间与域内变化的跨域行人重识别算法

针对单域训练的行人重识别模型迁移到另一个域内测试时性能巨大下降的问题,提出一种结合域间与域内变化的跨域行人重识别算法。采用PR策略将行人特征图进行分区处理,提高模型泛化能力。针对域间变化,引入域间姿势不变性,缩小源域和目标域行人的姿势差距。针对域内变化,引入域内姿势不变性、样本不变性、邻域不变性和相机风格不变性,扩大不同行人之间的距离,缩小相同行人之间的距离。实验表明,PR策略和5个不变性能有效地增强跨域行人重识别中的域自适应性,与只注重域间变化或域内变化的算法相比,其识别精度得到有效提升。