快以太网物理层的测试

以太网的物理层以太网是计算机区域网和广域网的基础设施,由于结构简单、灵活性强、传输速度高、价格合理,以太网已成为台式计算机网络的主导。10Mb/s的以太网用户最多,100Mb/s的以太网开始装备高速的用户,1000Mb/S的以太网正在发展中,因此以太网是名副其实的跨世纪网络。物理层是任何网络的电气连接     

以太网安全机制

以太网是目前最常见的用作接入网和校园网的传输网络,因此,大多数用户终端通过以太网接入Internet,以太网的安全性直接影响着整个网络的安全性,本文详细讨论了以太网多种用于防止黑客攻击的安全机制。     

以太网安全机制

以太网是目前最常见的用作接入网和校园网的传输网络,因此,大多数用户终端通过以太网接入Internet,以太网的安全性直接影响着整个网络的安全性,本文详细讨论了以太网多种用于防止黑客攻击的安全机制。     

以太网MAC帧检测与显示方法研究

为了解决用户只能通过书面资料理解以太网MAC帧格式的问题,本文实现了一种基于微处理器S3C44B0X的以太网MAC帧的检测与显示方法。系统通过电压比较器将双绞线上脉冲信号转换为微处理器可识别的二进制信号,完成完整以太网MAC帧的采样与曼彻斯特编码的解码,并通过液晶将实验结果进行显示。实验表明,该方法可以捕捉到未经以太网控制器处理的完整的以太网MAC帧,并使用户通过显示液晶对MAC帧中用户无法干预的字段进行分析。     

方兴未艾的100Mbps快速以太网

当以太网(Ethernet)刚刚面世时,10Mbps的数据传输速率似乎已经很快了,但是今天的网络用户已越来越认为它不能适应使用要求.因此,IC和局域网(LAN)系统厂商正急于定义一种更快的以太网,一种传输速率为100Mbps的以太网.目前正在涌现两种截然不同的IEEE快速以太网标准,但都还未全部制订完毕.不过,些公司已经公布了他们自己的100Mbps以太网版本.人们之所以需要快速以太网,这出于两方面的因素:入网用户越来越多;用户对带宽的需求越来越高.用户数量的增加意味着在一个共用网络中,提供给每一用户的平均带宽正在缩减.据国际数据公司(IDC)估计,每一网络网段的用户平均数将会从1991年的12个增加到1994年的21个.这样,每一用户的平均可用带宽将缩减40%多.     

用带有以太网MAC的Virtex-5进行系统设计

以太网是一个占有对优势的固线连接标准.Xihnx Virex-5以太网媒体接入控制器(以太网MAC)模块提供了专用的以太网功能,它和Virtex-5 RocketIO GTP收发器以及SelectIO技术相结合,能够让用户与各种网络设备进行连接.     

城域以太网颠覆性技术:PBT

北电近日宣布了一项新开发的以太网技术——PBT(运营商骨干网传输)。PBT的可靠性和确定性堪比SONET和SDH,同时保持了以太网低成本和简易性的特点,并拥有更强的扩展性。运营商采用这一技术,可方便地使用以太网为企业用户和住宅用户提供实时服务。     

基于SoPC的千兆以太网接口卡的设计和实现

研究并设计了一种基于SoPC的千兆以太网接口卡,重点对千兆以太网接口卡的组成、工作流程、EMAC、时钟管理、用户逻辑设计和软件设计等关键技术进行了描述,并基于Xilinx平台验证了千兆以太网接口卡的有效性。本文的研究为基于SoPC实现自主化的千兆以太网产品具有一定的工程参考价值。     

用户侧VLAN在光接入网中的应用

在接入网中,基于光纤以太网的接入技术使用已经越来越广泛。在传统的DSL 技术中, VLAN主要用来区分不同服务提供商的不同业务,对于用户侧的端口,可以通过不同的PVC来标识用户所使用的业务。针对于光纤以太网接入技术的使用,不具备传统DSL技术中的PVC来标识用于所使用的业务,通过在用户侧的端口上为用户分配不同的VLAN,使得在光纤以太网中同样能基于同一个端口提供不同的业务。     

千兆以太网纵横谈

随着技术的创新和应用的复杂化,越来越多的企业用户选择千兆以太网来构筑他们的高性能网络。特别是Internet应用、多媒体应用以及企业运作中的高级应用推动了市场对千兆以太网的需求。在评估和选购千兆以太网解决方案的时候,企业用户应选择价格合理、简单易用、可靠、先进的标准化产品,确保与现有网络设备之间的兼容。     

Ethernet passive optical network (EPON): building a next-generationoptical access network

This article describes Ethernet passive optical networks, an emerging local subscriber access architecture that combines low-cost point-to-multipoint fiber infrastructure with Ethernet. EPONs are designed to carry Ethernet frames at standard Ethernet rates. An EPON uses a single trunk fiber that extends from a central office to a passive optical splitter, which then fans out to multiple optical drop fibers connected to subscriber nodes. Other than the end terminating equipment, no component in the network requires electrical power, hence the term passive. Local carriers have long been interested in passive optical networks for the benefits they offer: minimal fiber infrastructure and no powering requirement in the outside plant. With Ethernet now emerging as the protocol of choice for carrying IP traffic in metro and access networks, EPON has emerged as a potential optimized architecture for fiber to the building and fiber to the home     

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。     

基于WiMAX的VPN租用线路服务

介绍了基于WiMAX接入的VPN租用线路服务,提出了一种用户的以太网数据通过WiMAX网络接入VPLS网络,建立端到端的以太网环境的解决方案,并给出了一个应用实例。     

A broadband utopia [fast broadband connectivity]

The Utah Telecommunication Open Infrastructure Agency (Utopia) promises to deliver to each of its 3,000 subscribers high-speed Internet access, telephony and television programming through a fiber-optic cable at data rates that reach 30 megabits per second. Encompassing 14 cities in the northeastern Utah, the optical-fiber broadband network is expected to soon reach speeds of 50 and even 100 Mb/s. Because Utopia sends TV programming as Internet packets, it puts a huge reservoir of bandwidth at the disposal of its providers. In addition to its dedicated bandwidth connections, Utopia relies on the Ethernet standard to carry Internet protocol data packets all the way from the central office to the individual subscriber without changing the format, greatly simplifying the network.     

Fiber-to-the-home services based on wavelength-division-multiplexing passive optical network

It is anticipated that more than 75 Mb/s per subscriber is required for the convergence service such as triple-play service (TPS). Among several types of high-speed access network technologies, wavelength-division-multiplexing passive optical network (WDM-PON) is the most favorable for the required bandwidth in the near future. Furthermore, WDM technologies, such as athermal arrayed-waveguide grating (AWG) and low-cost light source, have matured enough to be applied in the access network. In this paper, the authors propose and implement a WDM-PON system as a platform for TPS. The system employs an amplified spontaneous emission (ASE)-injected Fabry-Pe/spl acute/rot laser diode scheme. It has 32 channels of 125 Mb/s and adopts Ethernet as Layer 2. Multicast and virtual local area network features are used for the integration of services such as Internet protocol high-definition broadcast, voice-over Internet protocol, video on demand, and video telephone. The services were demonstrated using the WDM-PON system.     

Broadband access over cable for next-generation services: a distributed switch architecture

The hybrid fiber coax architecture deployed by the cable service providers has been successful in capturing a substantial piece of the residential broadband access market. In the United States over five million homes connect to the Internet using DOCSIS cable modems. We describe an evolution path to enhance the HFC plant to provide, initially, Gigabit Ethernet (and eventually multi-Gigabit Ethernet) on the trunk and feeder portions, and 100 Mb/s Ethernet on the subscriber drops. This next-generation HFC network will enable cable service providers to address the vast and underserved small and medium-sized business market, as well as offer emerging applications and services to the residential market.     

Ethernet PONs: a survey of dynamic bandwidth allocation (DBA) algorithms

Optical networks are poised to dominate the access network space in coming years. Ethernet passive optical networks, which leverage the ubiquity of Ethernet at subscriber locations, seem destined for success in the optical access network. In this article we first provide a brief introduction to Ethernet passive optical networks, followed by a discussion of the problem of dynamic bandwidth allocation. We then introduce a framework for classifying dynamic bandwidth allocation schemes and provide a comprehensive survey of the dynamic bandwidth allocation methods proposed to date. We conclude with a side by side comparison of the schemes based on their most prominent characteristics, and outline future developments of dynamic bandwidth allocation schemes.     

基于以太网传输MPEG-2码流的协议研究

从以太网作为MPEG-2码流传输的承载体出发,提出了一种新的基于以太网链路层传输MPEG-2码流的协议.阐明了新协议的构架和现有IP协议的关系,并在标准以太网帧结构基础上对此协议的封装进行描述和定义.对使用该种协议传输数字电视MPEG-2码流的服务质量进行分析,提出了一种较为切实可行的传输服务策略.仿真实验验证了采用该协议在一定网络负载下传输MPEG-2码流的可行性.     

一种点对点百兆入户的同轴接入技术

本文结合基带EoC的星形交换网络拓扑和有源EoC的高频谱利用率的优点,提出并实现了一种基于EoC(Ethernet over Coax)技术的独享百兆入户的宽带同轴接入技术P2P-ECAN(Point-to-Point Ethernet Coax Access Network)。论文全面阐述了该ECAN技术的系统结构、关键技术,并对网络性能进行了测试,测试结果表明该技术具有低成本、带宽宽、时延小的优点,完全满足广电下一代的接入网的传输要求。     

Self-adapted algorithm to provide multi-profile bandwidth guarantees in PONs with symmetric and asymmetric traffic load

A novel bandwidth assignment algorithm in Ethernet Passive Optical Networks with different coverage, called DySGAB, is proposed to provide subscriber differentiation. In contrast to algorithms which allocate bandwidth based on fixed weighted factors, DySGAB continuously adapts the bandwidth assignation to fulfill the requirements of all profiles, leading to an outstanding performance. This auto-adjustment, which has not been implemented in any of today??s algorithms, allows the network to evolve automatically to the stipulated values even if they change in real time. As a result, not only does DySGAB ensure the guaranteed bandwidth for every subscriber, but also is independent of the initial bandwidth restrictions, which is an advantageous characteristic for service providers.