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 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.     

千兆以太网测试设计与实现

随着城域网数据业务的增多和功能的增强，以太网服务在网络服务市场占据了主导优势，为了适应以太网专线、SDH上的以太网、多业务传送平台及光纤通道、VoIP及NGN等各种业务测试发展的需要，有必要针对千兆网络进行标准测试．文中主要介绍了千兆以太网测试的技术指标，提出一种测试方案，并给出具体的实现方法。     

光纤以太网技术在城域网中的应用

光纤以太网网是指在光纤上运行以太网局域网（LAN）数据包接入服务的网络，底层连接可以以任何标准的以太网速度运行，包括10Mbit/s、100Mbit/s、1Gbit/s或10Gbit/s。光纤以及网把以太网技术扩展到LAN之外，进入城域网（MAN）。光纤以太网也将以太网的优越性扩展到了MAN，大大降低了运营商的网络建设成本。     

FTTP技术的新宠--有源以太网

虽然无源光网络(PON)一直被美国的RBOC(地区性贝尔运营公司)选为光纤到驻地(FTTP)的支撑技术，但是仍有许多制造商和网络运营商推出另一种能够最佳利用以太网和IP(因特网协议)的有源以太网(Active Ethemet，AE)技术。为此，基于有源以太网网络结构和特点，从传输距离、成本、带宽、组网的灵活性、可靠性、维护的简便化等方面对两者进行了深入、细致的比较，最后得出结论，AE的优势明显，各网络运营商应该予以重视。     

Experience with PACS in an ATM/Ethernet switched networkenvironment

Legacy local area network (LAN) technologies based on shared media concepts are not adequate for the growth of a large-scale picture archiving and communication system (PACS) in a client-server architecture. First, an asymmetric network load, due to the requests of a large number of PACS clients for only a few main servers, should be compensated by communication links to the servers with a higher bandwidth compared to the clients. Secondly, as the number of PACS nodes increases, the network throughput should not measurably cut production. These requirements can easily be fulfilled using switching technologies. Here asynchronous transfer mode (ATM) is clearly one of the hottest topics in networking because the ATM architecture provides integrated support for a variety of communication services, and it supports virtual networking. On the other hand, most of the imaging modalities are not yet ready for integration into a native ATM network. For a lot of nodes already joining an Ethernet, a cost-effective and pragmatic way to benefit from the switching concept would be a combined ATM/Ethernet switching environment. This incorporates an incremental migration strategy with the immediate benefits of high-speed, high-capacity ATM (for servers and high-sophisticated display workstations), while preserving elements of the existing network technologies. In addition, Ethernet switching instead of shared media Ethernet improves the performance considerably. The LAN emulation (LANE) specification by the ATM forum defines mechanisms that allow ATM networks to coexist with legacy systems using any data networking protocol. This paper points out the suitability of this network architecture in accordance with an appropriate system design     

新一代的以太接入网

接入网是一个公共的网络环境,应用以太网技术需要解决用户信息隔离、用户管理和业务保证等问题。目前的以太网接入解决方案存在不少问题。适于公共网络环境的新一代以太接入网方案具有高度的信息安全性和强大的网管功能,可以保证用户的接入网方案具有高度的信息安全性和强大的网管功能,可以保证用户的接入带宽,而且成本低廉,将在今后的宽带接入中发挥重要作用。     

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.     

Dynamic Bandwidth Allocation Algorithm for Multimedia Services over Ethernet PONs

Ethernet passive optical networks (PONs) are an emerging access network technology that provides a low‐cost method of deploying optical access lines between a carrier's central office and a customer site. In this paper, we propose a new algorithm of dynamic bandwidth allocation for multimedia services over Ethernet PONs. To implement the suggested dynamic bandwidth allocation algorithm, we present control message formats that handle classified bandwidths in a multi‐point control protocol of Ethernet PONs.     

以太网知识讲座(8)--以太网网络组织及其管理

系统地介绍了以太网的基本概念、介质接入控制和物理层准规范、以太网信号的帧结构、网络的硬件设备、网络的组成及主要性能，以及以太网信号在PDH、SDH／S0NET中的传输等等。本部分主要介绍以太网的网络组成及其性能和网络管理。     

以太网电路仿真技术及其应用

在无连接的分组交换网络中,仿真电路交换业务可以采用电路仿真技术。时分复用(TDM)业务对时延、抖动以及分组丢失等特性非常敏感,因此电路仿真要解决的根本问题就是确保仿真业务的服务质量特性要求。由于以太网具有廉价、简单、扩展性强和分布广泛等特点,通过以太网传送TDM业务的需求变得越来越明显。以太网电路仿真技术可以实现以太网透明地传输TDM业务(E1/T1和E3/T3等)。文中主要介绍了TDMoverEthernet技术的基本概念、技术要点及面临的主要技术挑战;通过与TDMoverIP、VoIP和ATM等相关技术的比较,指出了该技术的优势;最后,给出了TDMoverEthernet技术的一个应用实例。     

以太网供电技术简介

传统网络设备的供电都需要本地交流电源来提供电能，不但增加了网络基础建设的成本，而且网络设备还可能受到电网掉电的影响。文中分析了通过以太网线同时传输数据和电能的以太网供电技术的基本工作原理及其发展，并结合一颗符合以太网供电技术标准的电源管理芯片，简要介绍了以太网供电设备的参考设计。     

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.     

Novel access technology based on hybrid Ethernet passive optical network and Ethernet passive electronic network

To improve the limitations of Ethemet over Coax (EoC) technology in the bidirectional reformation of the hybrid fiber-coaxial (HFC) network, this paper proposes the concept of Ethernet passive electronic network (EPEN) based on multi-point control protocol (MPCP) and the hybrid access scheme of Ethernet passive optical network (EPON) and EPEN.This paper describes the network architecture of EPEN, and introduces the implementation scheme and design of the EPEN system.At present, the project group has been working on the core technology research and key software and hardware design of the EPEN system, on which we have accomplished the hardware design and debugging, the embedded software coding and debugging, the EPEN network management protocol design and software coding.However, there is still a lot to do to achieve networking capability, management, security, quality of service (QoS) and some other functions.     

ITU-T有关EOT功能架构的标准与关键技术

本文根据最新的ITU-T研究进展,介绍、分析和总结了有关传送网承载以太网的传送功能架构,包括传送网分层网络模型的描述;以太网的分层结构与各层特征信息的详细描述;以太网的OTN/ETH等各类适配功能的分析、总结,网络拓扑结构的简要分析,以及相关标准的历史进程介绍.     

High-Speed Ethernet Transport [Standards Topics]

Driven by increasing bandwidth demand from increasing broadband penetration, video, and other high-bandwidth services, the IEEE 802.3 working group has proposed a new project on higher speed Ethernet, chartered with development of standards for new interfaces with medium access control data rates of 40 Gb/s and 100 Gb/s. As the impact of this technology will not be confined to large data centers, this paper explores the overall network context for higher speed Ethernet and the related evolution of the optical transport network.     

基于Ethernet的分布式虚拟仪器测试系统

本文介绍了虚拟仪器．分布式测试系统以及分布式虚拟仪器测试系统的概念，讨论了基于以太网的分布式虚拟仪器的设计思路，从网络基础、通信结构、软件系统等方面探讨其实现方法，并预测分布式虚拟仪器的发展方向。     

交换机中同步以太网技术的研究及其实现

本文提出了一种支持同步以太网交换机工作在主从模式状态下同步时钟网络架构,及其在不同工作模式下的时钟同步机制;提出了交换机工作在从模式状态系统同步链路时钟的优先级选择策略,以及工作在主模式状态下交换机系统时钟指定选择原则。实践表明,这种同步以太网时钟架构和同步机制能很好地满足网络应用。     

基于以太网的宽带接入技术

就我国国情和以太网技术特点，提出采用以太网接入技术，并针对其出现的问题介绍目前的解决方案，进一步引出新一代的以太接入网。     

Flush Optimizations to Guarantee Less Transient Traffic in Ethernet Ring Protection

Ethernet ring protection (ERP) technology, which is defined in ITU‐T Recommendation G.8032, has been developed to provide carrier grade recovery for Ethernet ring networks. However, the filtering database (FDB) flush method adopted in the current ERP standard has the drawback of introducing a large amount of transient traffic overshoot caused by flooded Ethernet frames right after protection switching. This traffic overshooting is especially critical when a ring provides services to a large number of clients. According to our experimental results, the traditional FDB flush requires a link capacity about sixteen times greater than the steady state traffic bandwidth. This paper introduces four flush optimization schemes to resolve this issue and investigates how the proposed schemes deal with the transient traffic overshoot on a multi‐ring network under failure conditions. With a network simulator, we evaluate the performance of the proposed schemes and compare them to the conventional FDB flush scheme. Among the proposed methods, the extended FDB advertisement method shows the fastest and most stable protection switching performance.