城域网核心路由器建设演进路线探讨

城域网核心路由器作为一个城市的核心出口路由器,其出口和汇聚能力至关重要,现网许多城域网的核心路由器采用40G平台的单机路由器,其槽位和能力有限,需要进行升级改造。本文提出了两种演进路线:升级为40G平台多机集群路由器和升级为100G平台单机路由器。通过初期投资、板卡扩容投资、节能减排等方面探讨了两种演进方式的优劣性。通过比较分析,证实先升级为100G平台单机路由器能有效地节省投资,并能较好地支撑业务发展,是城域网核心路由器升级建设的较优方案。本文还提出了城域网核心路由器上联骨干网核心路由器的链路结构调整方案,提高城域网上联链路的可靠性。     

高速路由器技术发展展望

路由器在Internet中起着举足轻重的作用,但是随着网上业务种类、业务量、用户数的迅猛发展,原有路由器在很多方面已经不能满足现在通信的需要,市场呼唤高速高性能路由器.高速高性能路由器是下一代高速网络的核心,自1997年第一个吉比特级路由器面世以来,高速高性能路由器迅速成为倍受瞩目的热点.     

高性能路由器技术体系、关键问题及发展趋势

网络用户规模的急剧膨胀、宽带用户业务需求日益迫切以及人们对用户服务质量(QOS)要求的不断提高，网络的宽带化和高速化建设势在必行。在宽带化和高速化网络中．网络路由节点必须由高性能路由器来承担，路由器的高性能主要体现在用户数据的处理容量大和处理速度快．以及协议的处理能力强三个方面。本结合作在高性能路由器方面的相关研究成果和科研项目的实际开发经验，比较全面地总结了高性能路由器的技术体系、关键问题和可能的发展趋势。     

T比特IPv4/v6高性能路由器设计与实现

互联网的高速发展,使得目前处于网络核心的路由器成为制约互联网可持续性发展的关键因素.随着网络新技术的引入和应用业务的增多,高性能路由器必须支持大容量、高吞吐率、低转发时延、IPv4/v6双协议栈和众多的路由协议.本文针对这些要求,详细阐述了T比特IPv4/v6高性能路由器的需求、系统设计、关键技术,为设计与实现高性能双协议栈路由器提供了一种可行的方案.     

Tbit路由器双协议栈的设计与实现

由于技术的进步和网络的日益复杂,网络路由技术发展迅速.自主研制开发国产高性能路由器在经济上、技术上以及安全上都具有重大的理论和现实意义.以实际的工作为背景,对于高性能路由器双协议栈进行了系统的分析,并对于双协议栈的实现和协议之间的信息交换进行了详尽的阐述,最后对高性能路由器进行了功能测试.满足项目的需要.     

基于Linux的IPv6协议栈在高性能路由器中的研究与实现

随着互联网的迅速发展和网络规模的急剧膨胀,构建新一代的IPv6网络和研制高性能的IPv6路由器成为IP网建设的当务之急。本文在对基于Linux操作系统的IPv6协议栈分析的基础上,重点讨论了IPv6协议栈在高性能IPv6路由器中的实现,并针对高性能IPv6路由器中邻居发现协议(NeighborDiscovery, ND)在主控上实现时带来的链路层地址解析问题提出了解决方案。     

集群路由器技术发展趋势

互联网业务的快速发展,导致对网络带宽的需求越来越大。而随着路由器单机容量的几近极限,运营商对集群路由器的需求越发强烈。文章首先介绍了目前市场上所能提供的集群路由器及其特点,分析了这些集群路由器普遍采用的三种交换结构：CLOS、BENES和TORUS,并指出了这几种交换结构各自的优势和缺点。最后,基于集群路由器的现状,文章就接口速率、稳定性、标准化等方面对集群路由器的发展趋势作了探讨。     

高性能路由器硬件抽象层的关键技术研究

分布式体系结构已成为高性能路由器普遍采用的实现结构，然而迫切需要解决的问题是如何实现独立于上层软件及底层硬件的通用性支撑软件体系结构。硬件抽象层的设计方案成功解决了该问题，本文对其在高性能路由器实现中的关键技术进行了详细研究。     

Netware异步远程路由器及其配置

Ｎｅｔｗａｒｅ异步远程路由器及其配置＠王建民Ｎｅｔｗａｒｅ异步远程路由器及其配置王建民使用帧中继、宽带数据交换（ＳＭＤＳ）、ＡＴＭ等广域网技术，借助高速通信链路创建互连网，无疑会使网络用户获得高性能的网络通信服务。但在很多情况下，用户承受不了这些高性能链路...     

一种基于网络处理器的高性能安全路由器研究

安全路由器是解决网络安全问题的关键设备，可编程的网络处理器解决了安全路由器实现中面临的灵活性、业务丰富能力及可扩展性等难题。本文分析研究了安全路由器的技术体系、IXPl200网络处理器的功能特点．给出了一种基于IXPl200网络处理器的高性能安全接入路由器解决方案。     

基于流量分析系统实现对3G基站FE口性能的优化

在移动网络数据业务大发展的背景下,基于现网中阿朗设备基站网管系统无法直观提供基站上下行最大流速、平均流速、坐标流量图和上网用户行为等功能,不便于我们日常对网络进行维护和优化,但通过结合挂接于FE路由器的流量分析系统的流量采集可以弥补此方面的不足。     

网络模拟中的路由器模型

文章通过对路由器体系结构和性能指标的分析,提出为网络模拟中的路由器建立模型的方法,为网络模拟网络总体设计提供了参考,给出了JuniperM160路由器和Cisco12008路由器在网络模拟中的模型实例。     

Defending against distributed denial-of-service attacks with max-min fair server-centric router throttles

Our work targets a network architecture and accompanying algorithms for countering distributed denial-of-service (DDoS) attacks directed at an Internet server. The basic mechanism is for a server under stress to install a router throttle at selected upstream routers. The throttle can be the leaky-bucket rate at which a router can forward packets destined for the server. Hence, before aggressive packets can converge to overwhelm the server, participating routers proactively regulate the contributing packet rates to more moderate levels, thus forestalling an impending attack. In allocating the server capacity among the routers, we propose a notion of level-k max-min fairness. We first present a control-theoretic model to evaluate algorithm convergence under a variety of system parameters. In addition, we present packet network simulation results using a realistic global network topology, and various models of good user and attacker distributions and behavior. Using a generator model of web requests parameterized by empirical data, we also evaluate the impact of throttling in protecting user access to a web server. First, for aggressive attackers, the throttle mechanism is highly effective in preferentially dropping attacker traffic over good user traffic. In particular, level-k max-min fairness gives better good-user protection than recursive pushback of max-min fair rate limits proposed in the literature. Second, throttling can regulate the experienced server load to below its design limit - in the presence of user dynamics - so that the server can remain operational during a DDoS attack. Lastly, we present implementation results of our prototype on a Pentium III/866 MHz machine. The results show that router throttling has low deployment overhead in time and memory.     

Distributed control and resource marking using best-effort routers

We present a method for creating differential QoS where control is in the hands of the end system or user, and the network distributes congestion feedback information to users via packet marking at resources. Current proposals for creating differential QoS in the Internet often rely on classifying packets into a number of classes with routers treating different classes appropriately. The router plays a critical role in guaranteeing performance. In contrast, there is a growing body of work that seeks to place more of the control in the hands of the end system or user, with simple functionality in the router. This is the approach outlined in this tutorial article: using insights from economics and control theory we show how cooperation between end systems and the network can be encouraged using a simple packet marking scheme. The network distributes congestion feedback information to users via packet marking at resources, and users react accordingly to obtain differential QoS     

政企互联网专线故障自动诊断系统研发

广州联通数据互联网智慧化运维系统是目前在数据网络监控和故障处理领域,最为行之有效的故障自动诊断系统之一。为提升大带宽业务的服务质量和提高网络安全水平,加速IP与IT的融合,提出了打造数据互联网智慧化运维系统。本系统以服务质量、用户感知、支撑效率、智慧运维为核心,率先将SDN&人工智能技术与传统网络维护相融合,针对影响互联网专线业务支撑效率的网络资源管理和影响用户体验的网络设备故障等难点痛点进行建模分析,利用大数据分析技术、IT信息化技术等手段,达到专线业务快速开通、安全事件迅速处置、网络瓶颈智能预警、网络故障自动处理的管控效果,完成对业务支撑、网络安全、故障响应和智能调整四个方面运维能力大幅提升,缩短故障历时,优化用户体验。     

路由器体系结构演变和未来发展趋势

随着通信传输网络向着超高速大容量的方向迅速发展，作为通信枢纽的核心中由器其线路速率愈来愈高，端口密度愈来愈大，体系结构愈来愈完善，本文综述了从路由器诞生之初到现在其体系结构发展演变过程，重点讨论了最新的第四代路由器体系结构及其需要解决的关键技术难题。     

The nominal capacity of wireless mesh networks

Wireless mesh networks are an alternative technology for last-mile broadband Internet access. In WMNs, similar to ad hoc networks, each user node operates not only as a host but also as a router; user packets are forwarded to and from an Internet-connected gateway in multihop fashion. The meshed topology provides good reliability, market coverage, and scalability, as well as low upfront investments. Despite the recent startup surge in WMNs, much research remains to be done before WMNs realize their full potential. This article tackles the problem of determining the exact capacity of a WMN. The key concept we introduce to enable this calculation is the bottleneck collision domain, defined as the geographical area of the network that bounds from above the amount of data that can be transmitted in the network. We show that for WMNs the throughput of each node decreases as O(1/n), where n is the total number of nodes in the network. In contrast with most existing work on ad hoc network capacity, we do not limit our study to the asymptotic case. In particular, for a given topology and the set of active nodes, we provide exact upper bounds on the throughput of any node. The calculation can be used to provision the network, to ensure quality of service and fairness. The theoretical results are validated by detailed simulations.     

Congestion Detection in the European Internet

In this paper we present a study about the utilization of one-way delay measurements to detect and characterize network congestion in the european Internet. The experiments have been made using the ETOMIC platform that allows one-way delay measurement with high precision timestamps. We have found a peculiar router behaviour in which the bottleneck is not the available bandwidth but it is the packet processing power of the router (backplane and CPU constraints). This router has been characterized with several network parameters. Some of them are the dependency of this limitation with the input data rate in packets per second, the size of burst packet losses measured in packets or time and the absence of specific scheduling algorithms in the router that could affect to larger flows.     

Bounds on the throughput of congestion controllers in the presence of feedback delay

We consider decentralized congestion control algorithms for low-loss operation of the Internet using the ECN bit. There has been much analysis of such algorithms, but with a few exceptions, these typically ignore the effect of feedback delays in the network on stability. We study a single node with many flows passing through it, with each flow (possibly) having a different round-trip delay. Using a fluid model for the flows, we show that even with delays, the total data rate at the router is bounded; and this bound shows that the (peak) total rate grows linearly with increase in system size, i.e., the fraction of overprovisioning required is constant with respect to N, the number of flows in the system. Further, for typical user data rates and delays seen in the Internet today, the bound is very close to the data rate at the router without delays. Earlier results by Johari and Tan have given conditions for a linearized model of the network to be (locally) stable. We show that even when the linearized model is not stable, the nonlinear model is upper bounded, i.e., the total rate at the bottleneck link is upper bounded, and the upper bound is close to the equilibrium rate for TCP.     

Packet reordering is not pathological network behavior

It is a widely held belief that packet reordering in the Internet is a pathological behavior, or more precisely, that it is an uncommon behavior caused by incorrect or malfunctioning network components. Some studies of Internet traffic have reported seeing occasional packet reordering events and ascribed these events to “route fluttering”, router “pauses” or simply to broken equipment. We have found, however, that parallelism in Internet components and links is causing packet reordering under normal operation and that the incidence of packet reordering appears to be substantially higher than previously reported. More importantly, we observe that in the presence of massive packet reordering transmission control protocol (TCP) performance can be profoundly effected. Perhaps the most disturbing observation about TCP's behavior is that large scale and largely random reordering on the part of the network can lead to self-reinforcingly poor performance from TCP