Gigabit Ethernet PCI adapter performance

We analyze the performance of a commercially available Gigabit Ethernet adapter, using TCP/IP running on a Windows NT operating system. We show how the performance varies with number of clients, sessions per client, number of system processors, and speed of system processors. Throughout, we discuss how the Ethernet protocol, adapter hardware, operating system, and device driver interact to produce the throughput results measured, and suggest ways to improve performance     

基于AOP的细粒度RBAC模型研究

提出一种新的基于AOP技术的RBAC访问控制模型,是对传统RBAC访问控制模型的改进,突破了传统RBAC模型中不具备对细分数据的访问控制的限制。同时,本文根据面向对象技术对不同种类的细粒度进行了有效抽象,采用现有Java Struts2和AOP技术进行了软件架构的设计,这种模型是一种通用的细粒度访问控制模型。本文所得出的细粒度RBAC模型具有较强的通用性,并在实际系统中得到了验证,取得了良好的效果。     

Power optimization and performance improvement for embedded Ethernet SOC

Information appliance is the combination of traditional home appliances and the internet technology. In this article, an Ethernet controller system-on-chip （SOC） solution for information appliances is presented. To achieve high performance, the embedded 8 bits 8051 micro control unit （MCU） is optimized by an independent instruction bus and a data bus. Besides, a two-stage pipeline feature is added. Compared with the existing 8051 core, the enhanced one-cycle MCU offers ten times improvement in instruction execution efficiency. Meanwhile, the performance of media access control （MAC） circuit is greatly improved by adopting various techniques such as direct memory access （DMA） control, paging strategy, etc. To reduce the power consumption, clock gating, low power supply, and multi-working-clock are adopted. Moreover, to achieve rapid data communication in different clock frequency circuits, a simple ping-pong first in first out （FIFO） circuit is realized. The chip is implemented using TSMC 0.25 μm two-poly four-metal mixed signal complementary metal oxide semiconductor （CMOS） technology. Its die area is 4.8 min× 4.6 mm. The test results show that the maximum throughput of Ethernet packets can reach 7 Mb/s while the power consumption is rather low-the working current is just about 200 mA.     

基于RFC 2544的以太网性能测试软件设计

针对RFC 2544标准的工程应用,设计了一种Win CE系统平台下的以太网性能测试软件方案,在此基础上详细讨论了包括以太网帧的构造、软硬件交互、数据管理和绘图操作在内的核心功能模块的实现方法.测试结果表明,该软件在硬件平台上运行稳定,功能执行正确,其代码具有较好的健壮性、有效性和可扩展性.     

客户观点的以太网业务模型与应用方案

文章基于IEEE 802．3以太网协议,通过加入业务相关曼性和参数来定义适合运营的以太网业务,并从业务的基本模型、业务的框架结构、典型业务的定义和典型应用方案几个方面进行了阐述。     

以太网收发器不断增加端口数量以提高网络利用率

以太网已成为最常用的企业通信标准之一.随着大多数企业从传统信息系统转移到基于网络的应用,各企业网络中的带宽利用率在大幅提高.     

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。     

A unified performance model for reservation-type multiple-accessschemes

This paper presents a unified performance model for an integrated voice/data wireless system using reservation type multiple-access (MA) schemes. It is observed that although these schemes are different in the frame structure and resource assignment procedure, all of them can be described by several common state variables whose evolvement exhibits the Markovian property. Based on this observation, a general Markovian model is developed in this paper. Three performance measures, namely, voice-packet-loss probability, data throughput, and data delay are defined. As a special case, the performance evaluation model for the voice-only system is also presented. Numerical results are given and verified by simulation under both voice-only and integrated scenarios using packet-reservation MA (PRMA), dynamic time-division multiple access (D-TDMA), and resource auction multiple access (RAMA) as examples. It is found that our analytical model is quite accurate, especially in the region of interest. The impact of system parameters (such as the voice-permission probability, data-retransmission probability, maximum number of voice slots per frame, etc.) on the integrated system performance is also investigated for these three example systems     

A model for calculation of magnetron performance

A simplified model of the space charge in a magnetron is proposed, and the performance of the magnetron is calculated; the method differs from that of Welch in the space charge density assigned to the "spokes," and from that of Hull in using energy conservation instead of the principle of induction to identify the operating point. The method is tested by applying it to four known magnetrons, covering a wide range of frequencies, operating voltages and power levels. In all four cases the method predicts the output power correctly within ± 0.5 dB, and the voltage within ± 2 percent, at the nominal operating current and field. It also predicts the frequency pushing, and provides information on the relative phase of the spokes, and other parameters. The spoke phase is found to be always within the range -20° to -60°.     

基于弹性以太环RER的研究

弹性分组环和以太网分别作为城域网和局域网重要技术之一,均有着独特的优点.在运营级以太网框架的下,基于以太网自身的基本协议和帧结构出发,把弹性分组环的管理机制和网络结构引入到以太网中去,提出新型的城域网络--弹性以太环RER方案.该方案进一步完善了以太网的相关协议标准,并使之满足运营级以太网的要求.     

T-MPLS层网络和以太网间基于PW的互通模型

目前的发展趋势表明,T-MPLS(传送多协议标签交换)将逐渐成为一种新的传送机制.文章介绍了端到端PW(伪线)模型,分析了T-MPLS网络的信号封装机制,提出了基于PW的T-MPLS层网络与以太网互通模型.在此基础上文章结合T-MPLS信号封装机制,详细讨论了基于PW的以太网互通模型.     

A general software reliability model for performance prediction

In this paper we give a general Markov process formulation for a software reliability model and present expressions for software performance measures. We discuss a general model and derive the maximum likelihood estimates for the required parameters of this model. The generality of this model is demonstrated by showing that the Jelinski-Moranda model and the Non-Homogeneous Poisson Process (NHPP) model are both very special cases of our model. In this process we also correct some errors in a previous paper of the NHPP model.     

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。     

交换机中同步以太网技术的研究及其实现

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.     

A constant slew rate Ethernet line driver

An analog bias circuit consisting of two transistors, three current sources, and one resistor facilitates the design of an Ethernet line driver. The rise time is insensitive to process variations and temperature variations, Rise-time accuracy is 223 ppm/°C over a temperature range of 140°C. This line driver has been fabricated in 0.35-μm CMOS     

通过以太网供电扩大以太网的应用

~~通过以太网供电扩大以太网的应用@Save Dwelley$凌特公司     

Fibernet II: A Fiber Optic Ethernet

This paper describes a fiber optic local area network which has been designed for use as an Ethernet and is currently operating at the Xerox Palo Alto Research Center. The fiber optic network, named Fibernet II, is an active-star configured network which is plug compatible with Ethernet at the transceiver cable interface. Collision detection is performed in the active star and collision presence is transmitted to the Fibernet transceivers. The performance and capabilities of Fibernet II are presented along with the motivation for the particular fiber optic implementation that was realized.     

PTN、MSTP网络承载以太网专线的性能对比分析

随着通信网络IP化趋势发展,PTN、MSTP技术在以太网业务的传输承载上得到了广泛应用。通过理论及现网测试两个方面对PTN、MSTP技术承载以太网专线业务的效率进行分析,总结得出PTN承载以太网业务时网络吞吐率的配置建议。