三种IP over SDH映射协议的比较

本文介绍了PPP／HDLC、LAPS和SDL三种IP over SDH的映射协议,对它们各自的特点进行了比较,指出SDL协议是最有前途的IP over SDH映射协议。     

IP网络中名址分离机制实现研究

文中分析了传统IP网络中的标识与编址体系存在的问题,指出了名址分离的必要性。研究提出了一种采用一个IP作为主机标识符,另外一个IP地址作为定位符,适应于通用型IP网络中实现名址分离的2IP方案,给出了该方案的总体体系结构、标识与地址的编址方式和映射维护、系统的协议组成,以及系统的通信流程机制等。并总结分析了方案的优缺点,以便于在实施过程进行选择和取舍。     

在SDH上传送IP的讨论

随着Internet的发展,Internet业务呈指数增长,对Internet的带宽要求也愈来愈大,为了满足用户不断增长的需求,Internet网络运营商和网络设备供应商开始使用和提供IP Over SDH技术和产品。 一、 IP Over SDH的定义 IP Over SDH以SDH网络作为IP数据网络的物理传输网络,它使用链路适配及成帧协议对IP数据包进行封装,然后按字节同步的方式把封装后的IP数据包映射到SDH的同步净荷中,IP Over SDH的定义如图1所示。 目前广泛使用点对点协议（PPP）对IP数据包进行封装,并采用高级数据链路控制（HDLC）的帧格式。PPP提供…     

PCI Express协议实现与验证

称为第3代I/O接口技术的PCI Express总线规范的出现,从结构上解决了带宽不足的问题,有着极为广阔的发展前景。基于Verilog HDL硬件描述语言及可综合化设计理念,完成了PCI Express IP核RTL代码的设计。IP核代码使用Verilog HDL语言编写,分模块、分层次地设计了事务层、数据链路层和物理层的逻辑子层,并进行了可综合化设计与代码风格检查。对设计的PCI Express IP核的功能分别从协议层次和应用层次进行了验证。具体实现上,采用Denali公司的PureSuite测试套件对IP核的协议兼容性进行验证,验证范围覆盖了IP核的3个层次以及配置空间,采用QuestaSim仿真工具对IP核的应用层进行验证。仿真结果表明,设计的PCI Express IP核工作正常,性能优良。     

多层网络中的生存性

未来传输网络中,不同的网络技术(如IP、SDH和WDM技术)的融合需要不同网络层次之间进行有效地配合,特别是网络生存性领域更是如此。首先对多层网络生存性机制的框架以及在多层网络环境下实现网络生存性的技术进行了概述,同时以IP over WDM为例,说明了这些方法的应用方式。     

基于FPGA的GFP成帧协议实现

本文介绍了采用XILINX的VIRTEX300E FPGA如何实现Ethemet Frame到SDH映射的GFP协议，详细阐述了GFP帧映射模式的原理及其实现的方法。     

标签交换光网络

IP对带宽的需求和WDM巨大传输能力的结合要求简化IP与WDM的协议模型。但运营商在传统语音和数据业务的投资使他们不可能在短期内从电路交换网络转移到带宽效率更高的IP/WDM网络上去。WDM技术能够提供多协议支持,彼此独立的不同网络协议可以在网络中共存,现有的、最常用的协议结构是IP/ATM/SDH/WDM（数据业务）和IP/HDLC/PPP/SDH/WDM（电路和专线业务）。目前的数据网络的四个功能层：IP层承载应用程序,ATM层处理流量控制,SDH层管传输,DWDM层提供大量带宽。这种多层叠加网络结构降低了网络效率,增加了网络操作…     

基于SDH的IP数据传输协议的分析

详细分析了PPP/HDLC,LAPS,SDL和GFP这四种基于SDH网的IP数据传输映射协议,研究了这些协议技术各自的优缺点.指出了SDL和GFP协议是未来更适合SDH网传送IP数据业务的链路层映射协议.     

基于口令认证的密钥协商协议研究

通过构建密钥协商协议为公开网络通信提供安全的会话密钥,保障通信安全。针对当前密钥协商协议抗攻击性能不好、公钥密码体制不安全的问题,提出基于口令认证的密钥协商协议设计方法。首先基于网络部署构建密钥预分配方案,采用Logistics混沌映射构建公钥加密方案;然后根据口令认证分组加密技术构建混合安全的密钥协商协议;最后通过仿真实验进行性能测试。实验结果表明,采用设计的密钥协商协议能提高密文的抗攻击能力,该方案的安全性得到证明。     

Ethernet over SDH接入技术

在以太网高速发展及SDH网络日益完善的今天,利用Ethemet over SDH技术将以太网的二层交换灵活性和资源优化能力与现有的SDH光网络的大容量、高带宽和低协议开销相结合,从而得到一种高速、经济的数据接入解决方案;实现了在SDH传输网上传送以太网数据包。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.