IP数据网络混和流的特性分析及模型化

IP数据网络流量分析模型的研究一直是通信网络性能分析中一个及其重要的问题。许多文献提出一些不同的流量模型,其中包括;马尔可夫模型、回归模型、长程依赖流量模型和(σ,ρ)漏桶模型。这些模型描述了网络流量的一些特性,并具有特定的使用范围。但是随着网络技术的发展和新网络应用的不断涌现,网络流量呈现出一些新的特性。通过对实际网络测试结果的时频分析,发现网络混合流的包速率变化呈现出一定的周期性,而且具有非平稳正态特性。基于此结果,该文提出了网络混合流的周期非平稳正态模型。     

基于下一代Internet的服务管理研究

Internet is best effort network, on the whole, it doesn't provide any quality of service assurance for services. Especially,all kinds of stream media need more network performance and quality of service. Currently, because of existing many heterogeneous networks, such as telecommunication network, IP data network , mobile network and so on ,in order to break off this heterogeneous network isolated complexion ,research and developmentnext generation network must be carried out,only by this way,can these isolated heterogeneous network be merged into an all IP network. This network will provide enormous services for service users,how to manage these services effectively is a topic proposed by next generation internet. [1] gave research status for service management and advance,this paper researches service management requirement for next generation Internet and workflow etc,and based on these technique,a service management architecture model is proposed. It consists of service access layer, service deployment layer, service providing layer, service mapping layer, policy control layer and network element managing layer. These layers coordinate to implement service management.     

Layer 2 over IP/MPLS

Over the past several years, traditional carriers and Internet service providers (ISPs) have invested billions of dollars deploying high-speed, high-capacity IP networks. This expansion is intended to lay the foundation for a network that could accommodate exponential traffic growth and deliver new revenue-generating services. Traffic from advanced services incorporating elements such as on-demand video, packet voice, wireless communications, and peer-to-peer networking is expected to consume whatever capacity providers can offer while leading to increased opportunities for revenue growth. The advanced services traffic has yet to materialize. An unintentional consequence of this buildout, however, is that ISP networks possess a glut of capacity. At the same time, ISPs are under great pressure to reduce operational and infrastructure costs while attempting to make money and attract customers with new services. One way to achieve both goals is to carry all traffic over a single IP or multiprotocol label-switching (MPLS) network     

Ingredients for better routing? Read the label

Administrators of wide-area IP networks-whether for Internet Service Providers or large corporate intranets-will face new and difficult challenges over the next few years. The growth of IP traffic is dwarfing the flat or modest growth rates of legacy (SNA, IPX) traffic. End-users are demanding consistently reliable performance for their network-based applications. Network managers are under pressure to enhance their infrastructures to support special or premium services for customers willing to pay for them. More bandwidth, lower network latencies, and high-speed traffic classification will be required to adequately support increased traffic volumes and new services     

VoIP development in China

Several factors have spurred the explosive growth of VoIP phone use in China, including customer incentives such as improved voice quality and lower cost per call, and provider incentives such as higher profits and upgrade paths to next-generation technologies. The voice over Internet protocol, also called IP telephony, offers a new type of service that uses the Internet protocol, intranets, and extranets to deliver voice information. In contrast to traditional telephone services, which operate through a circuit-switched network, VoIP uses a packet-switched network. This distinction results in differences in implementation, quality of service (QoS), and operating costs. Since the service was introduced to the public in China in April 1999, VoIP toll telephone traffic has increased with astonishing speed. By the end of 2002, VoIP toll telephone traffic had surpassed traditional toll telephone traffic in China in both domestic longdistance and international call areas, including phone calls to and from Hong Kong, Macao, and Taiwan.     

网络流场：理论和方法

随着互联网的迅猛发展,网络运营部门和网络管理部门迫切需要分析网络的运行状况,以保证网络的可用性、稳定性和安全性。然而,目前对网络运行状况的分析难度正逐渐增大,用户数量的快速增长,网络带宽的不断增加,网络流量的频繁变化以及新应用日趋复杂等,均给网络流量分析带来了巨大的挑战。因此,为了解决目前网络分析技术面临的难题和挑战,提出了一种网络流量分析的新型方法——网络流场理论和方法。网络流场不仅关注如数据包及网络流等“硬性”指标,而且更关注网络中的流量分布和发展趋势,因此能反映出网络流的分布以及节点之间的关系,从而反映网络的社会属性。网络流场以全新的视角对网络进行剖析,并进行定性和定量的分析,不仅能分析网络流量的基本信息,而且可以挖掘网络中的隐含信息,如时序关系、状态转换关系、私有网络拓扑、关键节点和关键路径等。实验结果表明,网络流场可以取得很好的分析效果,网络流场理论既可以有效地为现有的网络管理及网络分析提供更高层次的研究架构和研究模型,指导网络管理、分析、测量及安全保障等领域的研究和实践,又有利于网络的发展和技术的进步。     

A scheduler ASIC for a programmable packet switch

While the Internet is successful in supporting traditional data-only traffic, an integrated services Internet is inevitable with the emergence of new applications such as voice, video, multimedia, and interactive video conferencing. Such an integrated services network should support a wide range of applications with diverse quality of service requirements and traffic characteristics. Provision for quality of service in packet networks in general, and in the Internet in particular, is the focus of most of the recent developments in switching and routing system design. We designed a generic, single-queue scheduler engine for use in a programmable packet switch/router to handle IP packets, ATM cells, or a combination of both. Comprising 275,000 gates, the 0.35-micron ASIC is incorporated into a prototype programmable packet switch     

自适应网络流量线性预测算法及应用*

Internet网络流量的分析、模型仿真以及流量的预测,在网络管理和设计中起着很重要的作用。分析了CERNET网络流量行为,提出了CERNET IP Backbone的流量模型,同时将自适应滤波的新思想引入网络流量的模型仿真和预测,提出了自适应网络流量线性预测的新算法,并将其应用于CERNET的网络流量预测。     

SLA-based QoS pricing in DiffServ networks

The availability of high-speed transmission media and networking equipment in contemporary networks, as well as the evolution of quality-demanding applications has focused research interest on the provision of advanced qualitative services in addition to the traditional best-effort model of the Internet. A number of alternatives for service differentiation and QoS provisioning have been proposed and standardized, but in the case of backbone, transport networks the DiffServ architecture has prevailed, due to its scalability and deployment feasibility. The provisioning of services according to the DiffServ framework has in turn raised the requirements for interdependent, controlled resource allocation and service pricing, with particular needs for pricing mechanisms that preserve the potential and flexibility of DiffServ. At the same time, such mechanisms should reflect resource usage, allocate resources efficiently, reimburse costs or maximize service provision profits and lead customers to requesting services that will maximize their revenue. In this work, after reviewing related research, the principles that a pricing scheme for DiffServ-based services should follow are presented, stressing the differences form traditional Internet pricing. Based on these principles, an analytical approach to pricing a particular class of DiffServ-based services and a methodology for applying this approach in a real network are proposed and evaluated.     

DDoS攻击实时检测防御系统的硬件实现

分布式拒绝服务攻击是因特网安全的头号威胁。针对DDoS攻击,本文介绍了一种基于MPC860和FPGA的实时检测防御系统的体系结构与实现原理,探讨了基于非参数累积和(CUSUM)算法检测新IP地址到达速率变化的DDoS攻击检测方法。实验结果表明该系统不仅实时检测准确性高、在线检测速度快、防御效果好,而且不损失网络信息吞吐量,保证了合法用户的正常访问。     

基于主动网络技术的战术互联网无线子网的管理

为克服管理战术互联网无线子网的拓扑、设备状态以及流量工程的困难，提出了利用主动网络技术管理战术互联网无线子网的方法。在连接电台的战术互联网网关或互联网控制器上部署主动网管节点服务器，侦听网络相关信息，推测无线子网的拓扑和设备状态；依据报文的业务类型和链路状态，实时控制信息传输的路由和优先级，解决流量控制问题；允许用户动态定制无线子网的管理服务和管理策略。该方法提高了网络管理的实时性，减轻了网管业务对网络的负担，改善了网络服务能力，并与传统的管理体制兼容。     

Policy-Based Grooming in Optical Networks

This work presents a discussion about policies and architecture to aggregate Internet Protocol/Multiprotocol Label Switching (IP/MPLS) traffics within lightpaths. The scenario is that of IP/MPLS client networks over an optical network. It is well known that aggregating lower traffic flows (e.g., packet-based LSPs—Label Switched Path) within higher traffic flows (e.g., lambda-based LSPs) is considered an effective way to maximize the use of the optical network resources. In this work, the policies are divided into two groups. The first one, which solely considers the class of the flow (High Priority—HP or Low Priority—LP), consists of simple policies meant to aggregate packet-based LSPs within lightpaths. In this group, the policies we have defined intend to reduce the optical network overhead to remove and reroute LP LSPs. The second group presents more sophisticated policies taking into account the possibility of having to deal with further transport faults. In this case, the grooming is better planned and the defined policies tend to reduce the negative impact when a failure is detected in the optical transport network. Our approach has been implemented to validate the policies and the results for each group are showed and discussed.     

基于自适应滤波理论的网络流量线性预测

Internet网络流量的分析、模型仿真以及流量的预测，在网络管理和设计中起着很重要的作用。该文在此方面做了一些工作和尝试，主要有两方面的贡献：（1）在分析和比较了不同模型性能的基础上，提出了CERNET IP backbone的流量模型；（2）将自适应滤波的新思想引入网络流量的模型仿真和预测，提出了自适应网络流量线性预测的新算法。     

自相似网络业务流建模方法与比较

随着网络服务的发展．多媒体数据逐渐成为网络业务流的主要内容。基于多媒体数据的网络业务流对服务质量(QoS)提出了更高的要求。通常对服务质量的要求必然转化为对网络资源的需求，然而这个需求的量化必须基于一个能够准确描述网络变化的网络业务流数学模型。同时，网络业务流的不同特征以及研究目的的不同使得自相似网络业务流建模成为一个挑战性的问题。近来，一系列的方法被用于自相似网络业务流建模，本文的作者将这些方法分为两类共四种方法。本文全面分析比较了这些方法，并提出一种分类机制用于根据不同的研究需要确定相应的建模方法。     

基于多种服务并存网络的实时队列时延研究

高质量的网络服务是既能保证实时数据的正常传递,又能与Internet连通实现尽力服务,并且还能满足一定的带宽。而实时数据传输的最大时延是考核网络服务质量的重要指标之一。为此,论文给出了引入TCP拥塞控制算法后,同时满足带宽保证、实时与尽力服务三种服务的网络中实时队列最大时延的计算公式。     

基于DPI的流量识别系统的研究

随着网络应用的多样化,各种网络流量不断复杂化、多样化,各种网络安全事故频发.网络流量的分布不均匀以及网络安全状况的复杂使得互联网急需管理和维护,网络流量的监控问题变得尤为重要.流量识别作为一种能够自动、实时保障网络监控的技术,成为防火墙一类静态安全设备的必要补充,越来越受到人们的重视.深度包监测（DPI）技术以其识别的准确性成为应用越来越广泛的识别技术.然而单纯的软件实现系统监测速度较慢,不能满足网络高速数据包处理的吞吐量要求.单纯的硬件识别知识库会占用大量内存,一般的硬件内存达不到要求.单纯的软件识别效率又不能满足越来越大的网络吞吐量需求.这种情况下,文章研究了一种基于正则表达式的软硬件结合系统实现方法,该方法的主要思想是硬件识别网络常见协议,软件识别复杂的网络协议,且两者都支持正则表达式.这种方法兼具软件与硬件实现的优点,与传统的软件实现相比,在识别效率方面有明显提高.     

基于软交换的下一代网络技术

虽然因特冈发展快速，丰富多彩的数据型业务不断涌现，但受制于现有的电信网络和IP网络结构及技术，使如何开拓更多更丰富的服务成为当前的主要问题，而下一代网络(NGN)技术就是这些问题最佳的解决方案。本文介绍了下一代网络的基本概念和特点，分析了下一代网络的框架结构，其核心技术软交换(Softswitch)和相关协议，以及存在问题及发展前景。     

Internet服务管理技术综述

1 服务与服务的分类经常提到服务这个概念,那么到底什么是服务呢?文[1]对服务进行了定义:服务就是服务提供方向一个或多个所服务的用户提供的一组实际能力。为研究之便,我们将服务分成两类:一类是传输服务,另一类是应用服务。这两种服务并不完全独立,它们是相互依存的,其中传输服务是应用服务的基础与保证,而应用服务是对传输服务的一种增值与体现。应用     

TCP及TCP-friendly拥塞控制策略讨论

自从20世纪80年代报道了第一次拥塞崩溃以来，TCP拥塞控制策略在不断地进行完善和改进，通过快速重传和快速恢复等机制使它能很好地对网络拥塞做出及时的响应。但是随着网络技术的发展，音频和视频等多媒体业务(如IP Phone、视频会议)在网上的应用越来越多，而这些应用采用的一般都是不提供拥塞控制的协议(如UDP)，因此如何对这些业务流进行拥塞控制，使它们能与TCP流一起公平地共享网络带宽，满足TCP-friendly要求变得越来越重要。该文先对TCP拥塞控制进行讨论，然后对TCP-friendly拥塞控制策略和以后的研究方向进行了讨论。     

基于双种群遗传算法的MPLS流量工程研究

针对因特网流量的快速增加和对服务质量要求的不断提高,为避免网络数据流过大造成拥塞问题,利用MPLS流量工程的路由算法成为业界研究的重点。介绍了MPLS流量工程的工作机制,并提出了数学模型。MPLS流量工程的关键问题是LSP的分布优化问题,针对这一问题的Np-hard特性,提出一种基于双种群策略的遗传算法求解方法,算法采用自然数编码来提高搜索效率。算法中,两个子种群周期性地交流最优染色体,进一步提高了性能。仿真实验表明,提出的算法能有效提高搜索速度,增加获得最优解的概率。