有关千兆位以太网的常见问题

一、千兆位以太网技术 1.什么是千兆位以太网技术?它和10/100Mbps以太网有什么联系? 千兆位以太网是对取得巨大成功的10Mbps和100Mbps802.3以太网标准的一个扩展。千兆位以太网提供了1000Mbps的原始数据带宽,同时和现有的7000多万个以太     

卡接千兆 线通五类——谈千兆以太网卡

虽然目前大多数的千兆网卡还是光纤接口的,但铜线接口的千兆网卡正在崛起。尤其是利用五类线的千兆以太网卡,可以让现有的以太网及快速以太网随时升级到千兆以太网,而无需把成本花在昂贵的光纤上。2000年的千兆以太网卡销售量中,光纤接口卡占了85%;据业内人士预计,2001年铜线接口卡与光纤接口卡的销售量比例将是3:1。市场状况美国市场调查公司 Cahners-In-Stat的调查显示,千兆以太网市场每年增长     

FPGA与88E1111的千兆以太网接口设计

为实现设备间数据的以太网传输,对TCP/IP协议进行深入了研究,设计了基于FPGA和PHY物理层芯片88E1111的千兆以太网数据传输系统.系统采用硬件描述语言实现以太网传输协议,并利用Xilinx提供的M AC以太网控制器IP核完成帧校验和封装,物理层实现采用88E1111芯片.结合系统设计需求对TCP/IP以太网数据协议进行裁剪,仅保留UDP协议、IP协议和ARP地址解析协议.经测试,千兆以太网能够稳定、高效地实现数据传输.     

千兆网支持e时代传输

网络管理人员目前正转向依靠千兆位以太网技术来减轻其服务器连接、交换机堆叠和从工作组到数据中心的其它汇集点上的瓶颈。自１９９８年以来,业界就对使用光纤电缆的千兆位以太网进行了标准化,但是,直到最近还没有对第５类铜线电缆的千兆位以太网进行标准化,而第５类铜线是楼宇内使用最广泛的电缆媒介。过去,希望获得千兆位速度的网络管理人员经常面临用光纤给其楼宇重新布线的问题。今天,随着用于铜线传输千兆位以太网的１０００Ｂａｓｅ－Ｔ标准的批准,可以利用标准第５类电缆比较廉价地广泛使用于千兆位速度。互联网的作用随着很…     

心有千千兆

1998年6月,千兆以太网的标准IEEE 802.3z横空出世,以太网战车提速十倍,进入千兆时代,2002年6月,预计万兆以太网的标准IEEE 802.3ae将会出台,以太网战机?再次提速,万兆时代即将来临。然而,万兆以太网战机的腾空有待于千兆以太网的普及。尤其是对中国用户来说,千兆以太网已经到家门口了吗? 今年春节过后,实达网络展开了千兆普及行动,将其30多款千兆产品的价格下调了30％～50％。降价三至五成。可谓是重拳出击了。实达网络显然是认为中国的千兆市场该火了,千兆产品该普及了,所以才发起了这次冲锋。对于设备制造商的行动,应该认为是理性思考     

为千兆位铺“路” 布线和设备基础结构必须到位才可获得最高速度

对于面临带宽限制的网络经理来说,升级到千兆位以太网比其它技术具有显著优势,因为千兆位以太网的协议和包格式以是以传统以太网标准为基础。因此,网络经理从10/100Mbps以太网的故障排除过程中所获得的经验将能很好地帮助他们应付千兆位以太网。另外,千兆位以太网保留了其早期产品的帧格式、全双工操作和流量控制方法,从而消除了在不同类型以太网信息流之间进行转换的要求。不过,将一个网络升级至千兆位以太网也并非毫无困难。为充分实现千兆位以太网的优势,应当对布线基础结构和网络通信模式加以特别注意。     

千兆以太网中IP数据传输技术研究

本文主要讨论了多路千兆以太网中IP数据传输技术,详细介绍了MAC接收控制器的设计,为网络化测控仪器提供了一种经济高效的测试数据传输手段。该系统主要利用Altera公司的StratixII系列FPGA和Vitesse公司的千兆以太网PHY芯片,实现了8路千兆以太网信号中IP数据的收发功能。     

国际千兆以太网联盟(GEA)主席——Tony Lee即将来京

为加快国內千兆以太网的普及应用,北京凌威科技公司将于4月9日举办“千兆以太网研讨会”,并将邀请国际千兆以太网联盟(GEA)主席Tony Lee亲临会场,向国内用户介绍在千兆以太网标准尚未公布的现在,通过采用什么样的传输介质和工作站来使用千兆以太网。由于千兆以太网在传输上还存在问题,其原定于3月份推出的IEEE 802.3z标准也没能如期通过,所以该选择什么样的设备、怎样才能充分发挥出千兆以太网的最佳性能,     

基于千兆以太网的SAN的探讨

通过比较分析NSA和SAN基于光纤通道SAN和基于千兆以太网SAN,得出基于千兆以太网SAN的跨平台和硬件兼容的优越性,进而提出千兆以太网SAN的实现要求.     

USB 3.0/千兆以太网转换器的设计

为了实现高速USB与千兆以太网的转换连接,采用USB 3.0/千兆以太网专用转换控制芯片AX88179设计了USB/以太网转换器,并在充分说明AX88179芯片特性的基础上,给出了其以太网转换器的硬件电路设计方案及设计注意事项。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate