多协议标签交换网络的OAM机制研究与实现

多协议标签交换技术MPLS是可扩展的下一代网络的关键承载技术,为了保障其传输数据质量不依赖于其他服务层,需为其提供独立的OAM机制。文中基于Y.1711协议分析MPLSOAM的基本功能及实现。重点研究MPLSOAM报文传输功能,通过在系统中添加OAM报文转发模块实现,从而对MPLS网络数据平面缺陷的进行检测及定位,及时通知入节点进行保护倒换以维护网络高可用性、降低运营成本。     

T-MPLS的OAM特性分析

通过分析传送多协议标签交换(T-MPLS)网络的构建原理——在多协议标签交换(MPLS)网络基础上引入伪线技术。T-MPLS和MPLS网络结构的不同相应地带来了OAM(操作、管理、维护)需求的不同。通过对相关协议进行深入分析对比,说明了T-MPLS怎样加强和扩展了MPLS原有的OAM功能。然后讨论了体现T-MPLSOAM特点的嵌套过程的实现。最后针对协议中不甚完善的维护实体组层次(MEL)层数等内容提出了问题。     

MPLS网络中的OAM

网络操作、管理与维护（OAM）在公用网中非常重要,它能够提高网络可靠性,简化操作,降低网络运行成本。本讨论了在MPLS（多协议标记交换）网络中通过OAM数据包来实现OAM功能的方法,并在分析网络管理需求的前提下,提出了几种在MPLS层实现OAM功能的方案,展望了MPLS OAM标准的发展方向。     

分组传送网操作、管理和维护技术

为了适应面向连接的电信级业务传送,电信级操作、管理、维护（OAM）和保护,业务感知需求等,需要采用面向连接的分组传送技术。分组传送网（PEN）技术包括传送多协议标签交换（T—MPLS）和运营商骨干传送（PBT）。T—MPLS对MPLS技术进行了简化和改造,去掉了与传送无关的转发处理和无连接特性,并增加了传送层的网络模型、保护倒换和OAM功能;PBT技术着重加强了OAM和保护方面的特性,增加了TDM业务仿真和时钟功能,增强了多业务支持能力,关闭了传统以太网的地址学习、地址厂播以及生成树协议（STP）的功能。T—MPLS和PBT均很好地满足了分组传送的需求,T—MPLS相比PBT,OAM功能更完善。     

EPON系统OAM的实现

基于以太网的无源光网络(EPON)作为一种新兴的接入技术,需要网络设计者提供电信级(Carrier-class)的管理能力,而单纯的简单网络管理协议(SNMP)已经不能胜任其运营管理维护(OAM)的要求,正是由于上述原因,IEEE802.3ah工作组在新标准中专门规定了EPON系统的OAM协议.文章提出了基于802.3ah OAM协议和SNMP的EPON系统管理机制,并描述了EPON系统OAM的功能、特点以及在Linux操作系统下的该网络管理机制的软件实现方案.     

EPON的OAM子层研究

由于以太网技术的成熟和广泛应用,以太网无源光网络（EPON）接入方式已经成为宽带接入网技术的最新发展趋势.文章总结了EPON中的运行管理维护（OAM）功能、OAM协议数据单元（OAMPDU）和OAM子层组成模块,举例说明了其功能的应用过程,另外还简要讨论了OAM子层在网络管理中的作用。     

基于MPLS流量工程的故障管理实现方案

根据ITU-T(国际电信联盟远程通信标准化组织)的Y.1711,Y.1713标准,提出基于MPLS多协议标签交换)流量工程的故障管理模块实现方案.主要介绍对节点故障、链路故障和超流量三类故障的管理.故障管理模块检测到节.点错误和链路错误后,通知链路管理程序采用保护切换或重路由的方法解决.检测到超流量时,通知链路管理程序...     

运营级以太网中的OAM

OAM(运营管理和维护)是以太网技术从局域网向城域网和广域网发展过程中所面对一个主要问题.本文列举了运营级以太网对OAM的需求和挑战,介绍了以太网OAM在标准和技术方面的最新发展,并对其相关标准、协议机制和实现与应用等进行了阐述和分析.     

对以太网无源光网络中OAM的分析

以太网无源光网络(EPON)作为一种新兴的接入技术,需要网络设计者提供电信级(Carrier-class)的管理能力,而单纯的简单网络管理协议(SNMP)已经不能胜任其运营、管理、维护(OAM)的要求.文章提出了基于802.3ahOAM协议和SNMP的EPON系统管理机制,并描述TEPON系统OAM的功能、特点以及在Linux操作系统下该刚络管理机制的软件实现方案.     

基于REST的OAM的设计与实现

EBAS 是东信北邮下一代核心业务平台的重要组成部分,用于快速构建与部署电信增值业务的平台.OAM 对EBAS 运行时的管理和维护提供支持.针对OAM 目前基于协议适配架构存在难以扩展及维护等问题,提出了相应的解决方案,并给出了基于REST 的资源架构模型和统一接口的通用OAM 的具体设计与实现.     

城域网PBT技术中OAM的实现

主要介绍了OAM技术在PBT中的实现。首先说明了PBT相关技术,然后阐述了基于IEEE802．1ag和ITU—T Y．1731的OAM功能。分析研究了OAM技术在PBT上的实现。     

OAM mechanisms in MPLS layer 2 transport networks

This article describes OAM in MPLS layer 2 transport networks. MPLS networks used to transport layer 2 traffic are referred to as MPLS layer 2 transport networks. They may be used to connect legacy layer 2 networks and/or provide layer 2 service to a user over a MPLS network. As legacy layer 2 networks migrate to use MPLS for transport, the role of MPLS OAM mechanisms is becoming increasingly important. This is because the converged network must offer the same OAM functionality as existing layer 2 networks. This article emphasizes the importance of end-to-end OAM, while emulating existing layer 2 services using MPLS transport. End-to-end fault detection is described in the context of various layer 2 over MPLS transport network models. The article focuses on state-of-the-art MPLS label switched path and pseudo wire OAM mechanisms being developed by the IETF. This includes fault detection and isolation mechanisms such as LSP-Ping, bidirectional forwarding detection, and virtual circuit connectivity verification. The applicability of each of these mechanisms is given. In some cases it may be possible to carry layer 2 OAM cells end-to-end, while in other cases this may not be possible. The relationship between segment-based OAM mechanisms and end-to-end OAM is described for each of these cases.     

MPLS网络中的OAM机制

随着许多传统的基于电路交换的应用被放到基于包交换的IP／MPLS网络或者以太网上进行传输，包交换网络和电路交换网络之间的界限逐渐消失。为了提供和电路交换网络相同的QoS保证，包交换网络中也必须具备相同的OAM功能。首先对现有的基于IP的OAM功能做一介绍，然后就基于MPLS的包交换网络中如何提供OAM功能进行分析，最后讨论近期有关MPLS网络中OAM功能的一些建议。     

内嵌MPLS的多业务传送平台

为了提高多业务传送平台(MSTP)组网的路由能力、交换能力和服务质量(QoS)处理能力,需要将多协议标签交换(MPLS)的固有优势引入MSTP.方法是通过内嵌MPLS的MSTP,实现将以太网业务适配到MPLS层,然后映射到SDH通道中传送.MPLS技术通过将交换的概念引入MSTP,实现了数据流的统计复用和负载均衡;通过将QoS引入MSTP,实现了对各种新兴业务的支持;通过基于二层和三层技术的解决方案,在MSTP中实现了MPLS虚拟专用网(VPN);通过支持单向1 1、1:1标签交换路径(LSP)和MPLS快速重路由保护倒换,在MSTP中实现了MPLS的保护倒换机制.     

AT&T's MPLS OAM architecture, experience, and evolution

This article provides an overview of AT&T's MPLS OAM architecture, and gives examples of operational experience. Hallmarks of the architecture are a single, converged, and integrated MPLS/optical network, and the evolution to fully automated, zero-touch network operation. The concept of one converged IP/MPLS architecture will reduce operations, development, and capital costs. The concept of zero aims to bring full automation for every human-to-computer interaction currently required for setting up and maintaining network services, delivering services to customers in real time with zero defects and cycle time, and supporting both a network as well as an operational environment with six nines reliability. This approach effectively opens the network to the customer, enabling new levels of customer network management, service creation, and ordering, and empowering enterprise customers with the tools to create their own network services as they transform their own internal networks. In the article we describe AT&T's MPLS-enabled services, the corresponding MPLS operations architecture (including MPLS MIBs), our MPLS OAM operational experience, and MPLS OAM evolution needs for MPLS MIB enhancements and new network capabilities. By applying technologies such as artificial intelligence, self-healing/self-identifying network elements, expert systems, rules-based processes, and automatic speech recognition, the architecture will migrate from a predictive network that monitors, correlates, and recommends action; to an adaptive network that monitors, correlates, and takes action; to a cybernated network that has integrated components that dynamically manage by business rules and policies. We give several examples of how AT&T is already investing in and implementing this future vision, and conclude by challenging network researchers, developers, and key industry players to apply new technologies in fully realizing the operational vision.     

MPLS-TP的OAM机制基于FPGA的实现

操作、管理、维护（OAM）机制是加强对分组传送网络的管理和控制关键。继传输多协议标签（T-MPLS）技术以后,MPLS-TP吸收了三层IP、二层PWE3和一层TDM/OTN技术的优点,将OAM技术进行了继承和发展。作为分组交换网络（PTN）的主流技术,MPLS-TP必须拥有强大的OAM技术才能更加具备市场竞争力。主要对其硬件实现的方法进行了研究,首先详述了MPLS-TP网络的OAM网络模型及主要功能。重点对OAM功能硬件实现方式进行了讨论,提出了实现方案,详述了各个功能模块的逻辑处理过程及具体电路实现。方案还需要进一步的进行系统级的验证,将在今后的研究中会逐步完成。     

PTN and IP-Based Mobile Backhaul

Packet Transport Networks (PTN) combine the advantages of packet technology and Synchronous Digital Hierarchy (SDH) technology.Taking the packet switch as its core, PTN has a high statistical multiplexing ability, which allows it to become a more efficient packet transfer service. Its strong Operation Administration and Maintenance (OAM)-similar to SDH and carrier-class security protection services-ensures efficient mobile backhaul business management and transmission quality. MPLS Transport Profile (MPLS-TP) packet transport network eliminates connectionless features, such as Penultimate Hop Popping (PHP), label merge and Equal-cost multi-path (ECMP), and is enhanced in terms of OAM, protection, and synchronization. This is ideally suited for carrying IP-based mobile backhaul services and key account services. PTN, original Multi-Service Transport Platform (MSTP), Metro Ethernet, and IP over Wave Division Multiplexing (WDM)/Optical Transport Network (OTN) of organic complexes, contribute to an "all IP" era of telecommunications services.