IP VPN业务管理中可重用管理组件的划分和应用

IP VPN(基于IP的虚拟专用网)业务管理面临的主要难题是,TMN(电信管理网)管理层次模型中业务管理层不断扩展的业务需求,可重用业务管理组件是降低动态变化的业务需求带来的业务管理复杂度、灵活地定制和提供IP VPN业务的有效途径.本文首先分析了IP VPN的基本业务需求,提出了IP VPN业务属性的概念.在此基础上,从IP VPN业务属性的视点对IP VPN业务管理功能进行了划分,形成可重用的业务管理组件.最后,本文给出了一个业务管理功能向业务管理组件映射的实例.     

IP MAN中MPLS VPN部署和业务应用

IP城域网是一个城市地域范围内的IP网络,作为互联网的一部分,为用户提供基于IP的各种业务。MPLS VPN业务作为新兴的网络增值业务在提供本地连接通道的基础上,使企业的分支机构与总部间相互连通而不必建立专网,从而大大节约了企业的建网投入,为国内运营商提供了良好的市场商机。主要介绍中国联合网络通信有限公司荆州分公司利用MPLS VPN接入技术在IP城域网中实施部署。从CNC Network的局限性和业务需求入手,介绍了IP城域网中MPLS VPN部署工作的背景和意义。不仅对IP城域网中部署MPLS VPN的主要难点进行了阐述,还同时介绍了其在超市行业和金盾工程(GSP)中成功的业务应用。     

IP VPN在电信运营网络中的实现

本文论述了电信运营商进行IP VPN网络建设的必要性，并从技术的角度分析了基于网络型的VPN与基于用户设备型的IP VPN的区别。同时分析了MPLS/VPN网络在电信运营网络中实现的方法、路由的选择以及用户的接入方式，为电信运营商开展MPLS/VPN业务提供建设性的建议。     

MCE技术在VPN网络延伸应用中的探索和实践

以目前运营商广泛应用的语音IP承载网络架构为例,分析了现有VPN网络延伸存在的问题,并提出了解决方案。使用MCE技术作为承栽语音IP的VPN网络延伸,解决了现有语音IP承载网架构中存在的核心路由器冗余问题,并为语音接入点的接入层冗余提供了可能。     

10吉比特技术与MPLS技术结合促进IP网络电信化发展

当前IP城域网的建设从提高IP网络覆盖率,满足更多宽带用户的接入需求,逐渐转变为进一步提高VPN、专线、NGN等IP化电信业务支撑能力.将IP网络电信化,促进电信业务的IP化运营.在发展IP网的电信化的过程中,带宽、服务质量、网络健壮性,这几个基本条件需要保证.一些人简单的认为,10吉比特技术仅仅是对带宽的简单增加、MPLS技术的核心应用是为IP网提供VPN业务、MSTP城域光传输技术来提高网络健壮性.     

IPSec VPN远程接入MPLS VPN的几种方式

目前IP VPN业务在国内发展迅速,并且已经得到中国三大固网运营商中国电信、中国网通、中国铁通的高度重视。按照使用协议所在的层次划分,目前国内各大运营商提供的IP VPN业务主要可以分为M PLSVPN和IPSec VPN两种。M PLSVPN服务质量好、安全性高、接入带宽稳定,主要面向那些对价格不敏感的大集团客户,为客户提供高等级的业务和服务。而IPSecVPN接入灵活、不受运营商的接入条件限制,特别是目前三大固网运营商都受到本地接入的限制,所以IPSecVPN势必是M PLSVPN一种有益的补充。它主要面向那些对实时性、安全稳定性要求低,…     

H.323视讯网络的终端接入

本主要研究了H．323视讯网络的终端接入问题，即视讯终端配置公开IP地址或私有IP地址，通过不同接入方式(如专线、NAT／PAT、VPN等)实现视讯业务，同时着重分析了H．323视讯终端在防火墙存在情况下通过NAT／PAT接入的几种解决方案。     

VPN在双向NAT环境下的应用

根据私有网络环境的不同,VPN通信模式可分为三类:网关或客户端直接访问公网IP网关;网关或客户端通过NAT(地址映射)访问公网IP 网关;网关或客户端通过NAT 访问另一个NAT 后面的网关。为帮助用户在无需关心物理网络的接入地点、IP地址空间规划等问题的情况下构建 VPN,就必须解决双向NAT 穿透的问题。 所谓“双向NAT 穿透”的问题,实际上是指通信双方都在私有网络环境中(即采用保留IP地址上网),发起通信的VPN 设备由于无法确定被连接VPN 设备的IP地址和协商端口号,以及主要的安全协议IKE和IPSec都和传统的NAT 协议不兼容的…     

天博光电专栏利用AToM-MPLS任意传输技术提供二层传输服务

1背景 MPLS(Multi-Protocol Label Switching)多协议标记交换技术,属于第三代网络架构,是新一代的IP高速骨干网络交换标准.由于MPLS在VPN接入服务、流量工程及CoS/QoS等方面具有非常良好的性能,因此众多的广电系统运营商在进入电信服务领域时都采用了IP/MPLS技术构建自己的骨干网.     

基于IP承载网实现的移动分组业务承载方案研究

阐述了IP承载网的建设背景以及IP承载网的网络层次和结构,提出了分组业务网MPLS VPN业务的设计方案,并分别介绍了分组业务网的接入方式和分组业务网与IP承载网的互通方案.     

The IEEE P1520 standards initiative for programmable networkinterfaces

This article discusses the need for standard software interfaces for programming of networks, specifically for service and signaling control, through programming interfaces. The objective is to enable the development of open signaling, control, and management applications as well as higher-level multimedia services on networks. The scope of this effort includes ATM switches, circuit switches, IP routers, and hybrid switches such as those that provide for fast switching of IP packets over an ATM backbone. The basic ideas represented herein are in the process of development as a standard for application programming interfaces for networks under IEEE Standards Project IEEE P1520     

Wormhole IP over (connectionless) ATM

High-speed switches and routers internally operate using fixed-size cells or segments; variable-size packets are segmented and later reassembled. Connectionless ATM was proposed to quickly carry IP packets segmented into cells (AAL5) using a number of hardware-managed ATM VCs. We show that this is analogous to wormhole routing. We modify this architecture to make it applicable to existing ATM equipment: we propose a low-cost, single-input, single-output wormhole IP router that functions as a VP/VC translation filter between ATM subnetworks. When compared to IP routers, the proposed architecture features simpler hardware and lower latency. When compared to software-based IP-over-ATM techniques, the new architecture avoids the overheads of a large number of labels, or the delays of establishing new flows in software after the first few packets have suffered considerable latencies. We simulated a wormhole IP routing filter, showing that a few tens of hardware-managed VCs per outgoing VP usually suffice. We built and successfully tested a prototype, operating at 2×155 Mb/s, using one field programmable gate array (FPGA) and DRAM. Simple analysis shows that operation at 10 Gb/s and beyond is feasible today     

Xunet 2: lessons from an early wide-area ATM testbed

This paper is a retrospective on the design of Xunet 2, one of the earliest functional wide-area asynchronous transfer mode (ATM) networks. Work on Xunet 2 began in 1989 and the network, consisting of experimental ATM switches, IP routers, and 45 Mb/s transmission lines, has been operational since October 1991. The network serves as a “laboratory without walls” for eight research groups across the United States. While Xunet 2 has only a small number of nodes, it was designed as a prototype of a nationwide ATM network. This paper reviews some of the design decisions and lessons learned in the project and points out the research directions motivated by this work, focusing on the areas of traffic management, ATM switch design, network control, and the implementation of an IP router     

一种基于RIP和帧中继的网络设计

广域网和以太网是两种不同的网络技术,而小型局域网因为其业务多样性和分布离散性,使得其需要兼容不同协议的网络。提出一种基于以太网RIP路由协议和广域网的帧中继协议的网络设计,满足不同协议互通,为不同核心路由器和交换机之间配置RIP路由、静态默认路由和帧中继子接口,最终完成了该网络的布置。     

Mobility support for IP over wireless ATM

A wireless ATM system consists of a core network infrastructure that provides mobility support to end terminals and a wireless access link. This article outlines two schemes for supporting mobility of IP terminals in this network. In the first scheme, location management and handoff support is integrated within the ATM signaling and control framework (“mobile ATM”), and mobility is transparently supported at the IP layer by mobile ATM underneath. In the second approach, the IP protocol stack is directly executed on ATM switches (without an intermediate ATM signaling stack) using an IP switching technique called IPSOFACTO (IP Switching Over Fast ATM Cell Transport), and terminal mobility is supported via mobile IP     

Internet integrated service over ATM: a solution for shortcut QoSvirtual channels

In principle, the interaction of the resource reservation protocol (RSVP) and ATM should allow the IP level to benefit from some features of the ATM layer. The most interesting one is the native support of end-to-end quality of service provided by ATM. On the other hand, there are issues that must be clarified to define correct interworking: for example, the possible overlapping between the mechanisms used in the IP and ATM levels to support QoS, or the needed IP/ATM address resolution mechanism. This article proposes a solution to exploit ATM shortcut VCs supporting QoS in the Internet integrated services model. A straightforward enrichment to the RSVP protocol is defined, which only impacts the devices (hosts and routers) involved in the shortcut procedure. A mechanism for IP/ATM address resolution is provided, avoiding the use of other mechanisms such as NHRP. Special care has been taken to maintain compatibility with “traditional” RSVP hosts and routers     

On the provision of quality-of-service guarantees for input queued switches

While the Internet has quietly served as a research and education vehicle for more than two decades, the last few years have witnessed its tremendous growth and its great potential for providing a wide variety of services. As a result, input-queued switching architectures, because of their distinguished advantage in building scalable switches, are currently receiving a lot of attention from both academia and industry as an attractive alternative for developing future-generation ATM/IP switches/routers. However, the problem of designing scheduling algorithms with QoS guarantees for input-queued switches has always been known to be a very challenging problem. We give an overview of the efforts in designing scheduling algorithms capable of providing QoS guarantees for input-queued switches. These algorithms are classified under three categories: those based on slot time assignment, those based on maximal matching, and those based on stable matching. We also present some open problems on this topic as future research directions in this area.     

Designing Packet Buffers for Router Linecards

Internet routers and Ethernet switches contain packet buffers to hold packets during times of congestion. Packet buffers are at the heart of every packet switch and router, which have a combined annual market of tens of billions of dollars, and equipment vendors spend hundreds of millions of dollars on memory each year. Designing packet buffers used to be easy: DRAM was cheap, low power and widely used. But something happened at 10 Gb/s when packets started to arrive and depart faster than the access time of a DRAM. Alternative memories were needed, but SRAM is too expensive and power-hungry. A caching solution is appealing, with a hierarchy of SRAM and DRAM, as used by the computer industry. However, in switches and routers it is not acceptable to have a ldquomiss-raterdquo as it reduces throughput and breaks pipelines. In this paper we describe how to build caches with 100% hit-rate under all conditions, by exploiting the fact that switches and routers always store data in FIFO queues. We describe a number of different ways to do it, with and without pipelining, with static or dynamic allocation of memory. In each case, we prove a lower bound on how big the cache needs to be, and propose an algorithm that meets, or comes close, to the lower bound. These techniques are practical and have been implemented in fast silicon; as a result, we expect the techniques to fundamentally change the way switches and routers use external memory.     

GPON技术在移动网络中的研究

无源光网络一直被认为是光接入网中颇具应用前景的技术,它打破了传统的点到点接入方法,在解决宽带接入问题上是一种经济的、面向未来多业务的用户接入技术。目前用于宽带接入的PON技术主要有ATM PON、Ethernet PON、和GPON。随着因特网的快速发展和以太网的大量使用,针对APON标准过于复杂、在传送以太网和IP数据业务时效率低和EPON无法对传送实时业务提供高质量保证、缺乏电信级的网络监控等缺陷,由FSAN组织在2002年9月提出了具有高速率、高效率、支持多业务传输的吉比特无源光网络GPON。伴随着通信业务形式的改变,用户对整个通信网络的要求越来越高。作为最新技术的GPON能比较好地满足接入网的要求,有望成为下一代网络系统的主要接入技术。     

ATM switching and IP routing integration: the next stage inInternet evolution?

User demand for more bandwidth and QoS support has fueled interest in the use of ATM as an underlying link-layer technology in the Internet. The challenge is how best to exploit the potential benefits of ATM while maintaining the inherent strengths of the IP layer that have made the Internet so successful. The suitability of various schemes with regard to meeting these goals is described. In particular we focus on recent work that tightly integrates the IP and ATM layers to produce hybrid (or integrated) ATM switch/IP routers with very favorable characteristics