Scalable,hierarchical, Ethernet transport network architecture (HETNA)

Ethernet technology is not inherently scalable, and yet, Ethernet dominates LANs, and recently has diffused to access, aggregation networks, and MANs. Ethernet is even considered for transport networks in the backbone. Many solutions from IEEE, IETF, and MEF are considered for enabling Ethernet beyond LANs and bridged LANs. In this paper we offer HETNA, a hierarchical Ethernet forwarding, which is compatible with legacy networks used by enterprises, carriers, and backbone networks, and provides scalability, mobility, protection, multicasting, and QoS support to intra- and inter-domain networks in an efficient forwarding manner. The suggested architecture can handle streaming, real-time, multicasting, and other applications as well as various addressing mechanisms (e.g., IP or URI addressing). Both connection-oriented transport services and connectionless-oriented services are possible in the suggested architecture. This architecture was simulated and prototyped, showing significant improvements over regular Ethernet in terms of buffers and control messages that enable this network to function.     

新兴的光城域以太网业务及其标准

本探讨了当前以太网业务存在的问题和当前的解决方案，并介绍城域网论坛MEF、国际电信联盟电信标准部ITU—T等标准化组织在定义的新兴的光以太网业务，和其标准体系和最新情况。     

基于PON技术的光接入网络应用模式

无源光网络是当今宽带接入网领域中最为热门的技术之一,其树型拓扑可以实现以太网业务、模拟视频业务以及TDM业务的高速传送.本文首先对PON技术的发展情况进行了阐述,分析了其针对不同业务场景的典型应用方案,并根据技术、业务需求、成本以及政策现状,讨论了基于PON技术的光接入网络应用模式.     

电力SDH/MSTP传输网主站侧设备以太网资源优化

随着现代电网对数据通信业务需求的不断增加,地市供电公司SDH/MSTP传输网承载以太网汇聚业务的种类和数量增长迅猛。业务资源需要在主站侧传输设备汇聚落地,占用大量以太网虚拟端口(VCTRUNK)资源。由于SDH传输设备槽位和以太网板资源有限,造成主站侧传输设备资源紧张。针对此问题,从业务的数据类型和带宽需求出发,充分结合当前电力企业SDH传输网和综合数据网资源,采用以太网业务二次汇聚、转移业务至综合数据网以及SDH与综合数据网联合承载等方法,优化SDH/MSTP主站侧设备以太网业务承载方式。最后,通过实例验证所提方案能够显著减轻SDH/MSTP主站侧设备承载以太网业务的压力。     

城域宽带网QoS机制——多业务差异化运营的利器

多业务运营已经成为新时期运营商发展的趋势。在城域网领域，随着业务类型的多样化、业务流向，流量不确定性的增加，如何有效地标识用户，业务、提供完善的QoS机制成为多业务发展的关键。针对城域网现存的问题，电信级以太网技术通过多种增强技术（如ERP、QinQ、QoS、电信级网管等）为城域网提供完备的QoS机制和电信级性能。从多业务运营的需求出发，分析现网存在的问题和解决方式，剖析电信级以太网技术在满足城域网优化（特别是QoS提供）方面的特点，并最后对其发展趋势作出判断。     

Operation, administration, and maintenance of Ethernet services in wide area networks

Recent developments in Ethernet technology, such as 10G Ethernet interfaces, Ethernet passive optical networks, and resilient packet rings are pushing Ethernet from the local area network environment to metropolitan and wide area network environments. For Ethernet service providers, managing Ethernet services efficiently is key to a sustainable business model. This article discusses issues in providing OAM features and capabilities to Ethernet services over metro and wide area networks. We analyze current Ethernet features that can be leveraged in an Ethernet OAM framework, and introduce requirements and new functionalities to support Ethernet services in wide area networks.     

Ethernet services over mobile WiMAX

Ethernet services represent a steadily growing portion of the fixed telecommunication market. To enable the provisioning of Ethernet services over IEEE 802.16e, the mobile WiMAX network architecture supports transparent Ethernet transport as an optional extension to the IP services architecture. Ethernet support is tightly aligned to the IP services network model, and leverages many data path and control plane functions from its IP sibling to keep the implementation and operation overhead low for the Ethernet extension. Mobile WiMAX provides IP services as well as Ethernet services over the same mobile access network. The intrinsic mobility support may create new deployment opportunities for Ethernet services. Initially, the Ethernet extension may be mostly used to realize wireless access for DSL networks based on the same network interfaces defined for the wired Ethernet-based DSL aggregation.     

Impact of the evolution of the metropolitan network on the DSL access architecture

Without any doubt, broadband Internet access is one of the most successful services offered by telecom operators today. It gives the operator the potential of offering many new services to residential and business customers, thereby introducing new revenue streams. ATM today provides a solid solution for this. At the same time, packet-based aggregation technologies -especially Gigabit Ethernet are becoming popular for offering connectivity services to business customers. The success of packet-based aggregation technologies is mainly driven by their lower cost compared to established cell-based solutions. This article addresses a number of requirements that must be fulfilled by the access network if it is used to provide multiple services. It will be shown how MPLS and Ethernet can be used in a broadband access architecture. Both meet many of the identified requirements, but still require some standardization before reaching the same maturity as their cell-based counterpart. It will be shown how MPLS technology can be used to seamlessly link cell and packet-centric networks together. This gives operators the possibility to keep the benefits of their existing cell-based infrastructure and smoothly evolve toward a packet-centric approach when the time is right.     

电信级城域以太网电路仿真业务实现探讨

随着电信级城域以太网的广泛应用,以太网承载TDM业务的需求也越来越多,通过对几种常用电路仿真业务的描述和比较,探讨了电信级以太网中TDM业务的实现方法。     

Multiservice Ethernet access

Ethernet is evolving from its origins in the local area network into a cost-effective and reliable wide area network technology. Market research shows that business customers are moving away from traditional leased lines and selecting Ethernet as the access network technology of choice due to its low cost, simplicity and flexibility. Developments in Ethernet technology are now offering service providers the opportunity to deliver cost-effective carrier class Ethernet services. In particular, a new generation of Ethernet network termination equipment (NTE) is emerging which provides remote management, flexible bandwidth and fault diagnosis while supporting access to multiple services delivered over a single physical connection. This paper describes the advantages and potential cost savings of using Ethernet in the access network. A case study for a city demonstrates significant capital expenditure cost savings and highlights the advantages of using new Ethernet NTEs, which can be up to ten times cheaper than SDH technology, delivering equivalent bandwidth. Remote management and fault diagnosis features can also reduce operational expenditure by avoiding unnecessary site visits. A network architecture is presented which supports delivery of Ethernet services over a combination of circuit-switched and packet-switched domains. New standards which are maturing in the IETF, IEEE and ITU to support Ethernet delivery of interoperable services with carrier class reliability are also discussed.     

Ethernet-based public communication services: challenge and opportunity

Enterprises and residential customers increasingly take advantage of more sophisticated applications and evolve their business models. At the same time service providers face declining revenues from existing connectivity services. SPs respond to these trends and start to offer highly customized, high-bandwidth network services that complement and interwork with their existing leased line, ATM, or frame relay offerings. Ethernet is quickly becoming the customer UNI of choice. Ethernet, being a packet-based technology, complements IP-based services such as content, voice, data, video, and additional value-added services over a high-speed access connection. Ethernet also provides a flexible high-speed connection to the SP network and eliminates access bottlenecks. Using Ethernet as the common access interface, providers can employ flexible transport services that enable additional value-added services at layer 3 and above. At the same time the rollout of Ethernet services also challenges the installed base, given that bandwidth per customer is usually much higher and additional attributes for tight SLAs apply. This calls for an updated approach to network deployment and rollout: networks need to be planned and built in a service-centric fashion. Starting with a brief look at the driving forces for Ethernet-based public communication services, this article identifies five generic services for Ethernet MANs/WANs and discusses related deployment issues of the different service options, such as the degree of customization, geographic reach and bandwidth profile of the service, as well as evolution aspects of the installed base.     

Network high availability for ethernet services using IP/MPLS networks

Enterprises are increasingly using Ethernet as the foundation for transforming their networks to Internet Protocol. Simultaneously, service providers are deploying Ethernet to exploit the demand for wide-area Ethernet services and as the infrastructure for new residential services such as IPTV. This is due to Ethernet's low cost per bit and ubiquity in local area networks. Recent years have seen the widespread deployment of IP/MPLS networks to address this opportunity. IP/MPLS enables enhanced flexibility over the same converged network for IP and legacy services, avoiding the need to build separate per-service networks. It also adds carrier- grade capabilities such as quality of service, traffic engineering, and resiliency, thereby enabling new multipoint services such as virtual private LAN service. However, using Ethernet for ";always-on"; and other mission-critical services has resulted in new resiliency requirements, in both the access and the network core. Two novel developments address these high expectations by enabling significant improvements in service availability. These are pseudowire redundancy and Ethernet multi-chassis link aggregation. This article reviews the current redundancy mechanisms typically deployed in Ethernet and MPLS networks. We show how additional enhancements are required in both the network core and the access to the Ethernet service. We describe new pseudowire redundancy and MC- LAG mechanisms, showing how they work together to enable end-to-end protection for Ethernet virtual private wire services and VPLS.     

同步以太网测试方法

得益于移动宽带业务的强劲增长,许多移动网络运营商已经或正在把移动回传网络从传统同步传输(如SONET/SDH和T1/E1)迁移到运营级以太网。传统TDM网络不仅提供数据传输,而且能实现频率同步。这样,原来由TDM网络提供的时钟同步也同样必须在以太网络中实现,并且同步的质量和网络性能不能受到影响。再者,3G/LTE无线网络不仅需要频率同步,还需要时间/相位的同步。所以,在部署前对以太网络各个部件作同步性能的验证就显得非常必要。本文介绍了实现以太网同步的各种方式和原理、同步精度测量面临的挑战。结合IXIA业界领先的同步测试工具Anue 3500,重点对PTP技术中的路径支持设备(如边界时钟和透明时钟)的测试方法进行了探讨。     

Traffic engineering for ethernet over SONET/SDH: advances and frontiers

Continued growth in data services coupled with the entrenchment of existing carrier infrastructures have inevitably forced a convergence of SONET/SDH and Ethernet technologies. As a result, the very notion of Ethernet connectivity has expanded beyond traditional local area domains into broader metro/wide area settings. The key enabling advances have come in the form of improved SONET/SDH provisioning features as well as new carrier Ethernet services standards. These provisions have allowed carriers to build and deploy much improved multigrade point-to-point Ethernet line services and have also opened up new challenges for extended multipoint offerings. This article looks at this evolving area and summarizes recent advances in EoS traffic engineering. It also highlights some key future challenges and presents a novel scheme for multipoint services provisioning in EoS settings.     

移动多媒体网络中的无缝切换

第三代移动通信（3G）面临的一个重要的挑战就要要无缝集成固定和移动网络中的多媒体业务。对于移动用户来讲,网络支持的业务有图像、多媒体、数据以及不同服务级别的话音业务。为了满足以上业务需求,3G系统必须具有丰富的性能。如今普遍采用ATM技术的同质网络虽然支持很多用户,但此种网络结构不可能成为最终的解决方案（至少从学术界、网络设备制造商的观点来看）。而以太网家族中高速设备的快速发展,已经部分代替了ATM。同时基于因特网业务的爆炸性增长,已经确保IP仍将成为下一代系统网络层协议。本文讨论了IP网因支持移动业务而产生的问题,以及对切换技术进行的分析。     

Ethernet OAM: key enabler for carrier class metro ethernet services

The onset of Ethernet as a metropolitan and wide area networking, technology has driven the need for a new set of operations, administration, and maintenance protocols. Service provider networks are large and complex with a wide user base, and they often involve different operators that must work together in order to provide end-to-end services to enterprise customers. With enterprise end customer demands ever increasing, so have the requirements on service provider Ethernet networks increased, particularly in the areas of availability and mean time to repair. Ethernet OAM addresses these areas and more, and is a tool that translates directly to the competitiveness of the service provider. Ethernet OAM is a broad topic, but this article focuses on three main areas that are most in need by service providers and are rapidly evolving in the standards bodies: Service OAM, Link OAM and Ethernet LMI. These OAM protocols have unique objectives but are complementary to each other. Service OAM provides monitoring and troubleshooting of end-to-end Ethernet service instances, while link OAM allows a provider to monitor and troubleshoot an individual Ethernet link. There are of course many different ways to provide this type of functionality, but fortunately standards bodies such as ITU Study Group 13, IEEE 802.3 Clause 57 (formerly 802.3ah), IEEE 802.1ag Connectivity Fault Management, and the Metro Ethernet Forum are all driving toward consistent recommendations and standards for Ethernet OAM.     

以太网业务定义的探讨

以太网在局域网的成功得益于其高度的标准化,而以太网业务在电信网中的广泛应用也需要标准化的支持.本文首先介绍MEF和ITU-T对以太网业务的定义,然后对这两种定义进行分析和比较,最后在此基础上提出一种以太网业务定义的框架.     

A new carrier grade aggregation network model for delivering broadband services to fast moving users

In this article, we present the research challenges that are associated with designing a cost‐effective network architecture for delivering broadband services to fast moving users (e.g. in trains). We specifically extended the standard Switched Ethernet technology towards a truly Carrier Grade network solution for fast moving users. Prototype implementations allow us to evaluate dynamic tunnel setup mechanisms and to prove that fast Ethernet recovery is feasible by extending the existing spanning tree mechanisms. For architectures with multiple spanning trees the problem arises as to how the spanning trees have to be configured. Therefore, we propose time‐efficient algorithms which solve the problem of aggregating paths into a minimal set of spanning trees. In the performance evaluation section, we compare vulnerable centralized backup systems to systems relying on distributed spanning tree‐based recovery and it is shown that the former require more spanning tree instances to be configured than the latter for the same set of backup paths. The presented methods and results show that Ethernet technologies are well suited for building flexible and robust network solutions that can support fast moving users. Copyright © 2006 John Wiley & Sons, Ltd.     

在以太网中提供电路仿真业务的方法

文章介绍了以太网中提供电路仿真业务的应用参考模型,接着阐述了该业务的主要技术要求,最后提出了几种典型的电路仿真业务在以太网中的实现方案。     

Optimized routing for providing ethernet LAN services

Ethernet's-move into metropolitan and wide area networks is driving a rapidly growing market opportunity. Current Ethernet services come in two basic flavors, Ethernet line and LAN, providing point-to-point and multipoint connectivity, respectively. The LAN services, although more cost effective, are lagging behind in deployments due to associated QoS and bandwidth provisioning issues. The Ethernet service provider needs to provision the network to meet current and future traffic demands, where the traffic is unpredictable and bursty. The goal is to minimize. overprovisioning and complexity. To add to the challenge, Ethernet routing is based on simple self-learning and relies on spanning tree routing. In this article we propose an Ethernet-specific load balanced routing mechanism, which is robust to dynamic traffic demand. It significantly reduces overprovisioning, is simple and static, and requires only bandwidth profiles associated with service level agreements at the ingress and egress links. Our simulation results show that our scheme provides performance improvements over a recently proposed approach for switched Ethernet as well as a related load balancing approach for Ethernet over MPLS networks.