IP-VPN在GPRS网络中的应用

在向移动互联网的演进过程中，移动通信网的一个重大进步就是引进分组数据业务，在网络结构上与数据网融合。作为向移动互联网过渡的第一步，GPRS网络提供分组数据交换业务，第一次将IP网与移动通信紧密联系起来。根据ETSI关于GPRS规范的定义，GPRS管理数据和用户数据的传输遵循IP协议，由IP骨干网承载传输。IP网在各网络节点间承担连接、数据传输的任务。作为一种安全可靠的In－ternet访问通道，虚拟专用网（VPN）近年来越来越受到人们的关注。随着IP骨干网引入移动通信领域，VPN已成为一个移动通信网络设计的重要议题。VPN…     

IP-VPN在GPRS网络中的应用

在向移动互联网的演进过程中,移动通信网的一个重大进步就是引进分组数据业务,在网络结构上与数据网融合。作为向移动互联网过渡的第一步,GPRS网络提供分组数据交换业务,第一次将IP网与移动通信紧密联系起来。根据ETSI关于GPRS规范的定义,GPRS管理数据和用户数据的传输遵循IP协议,由IP骨干网承载传输。IP网在各网络结点间承担连接、数据传输的任务。作为一种安全可靠的Internet访问通道,VPN近年来越来越受到人们的关注。随着IP骨干网引入移动通信领域,VPN已成为一个移动通信网络设计的重要议题。VPN可以有多种不同的实现方式,其中包括各厂商提供的不同的技术。要在移动通信环境中设计、实施一个有效的IP-VPN,关键在于要分析好什么能最好地满足各种情形的需求,并充分考虑到安全性等重要因素,保护网络及其上所传信息的     

IP-VPN在GPR9网络中的应用

在向移动互联网的演进过程中，移动通信网的一个重大进步就是引进分组数据业务，在网络结构上与数据网融合。作为向移动互联网过渡的第步，GPRS网络提供分组数据交换业务，第一次将IP网与移动通信紧密联系起来。根据ETSI关于GPKS规范的定义，GPKS营理数据和用户数据的传输遵循IP协议，由IP骨干网承载传输。IP网在各网络结点间承担连接、数据传输的任务。作为一种安全可靠的Internet访问通道，VPN近年来越来越受到人们的关注。随着IP骨干网引入移动通信领域．VPN已成为一个移动通信网络设计的重要议题。     

Shasta IP VPN业务及案例分析

随着IPVPN在企业和服务供应商中普及率增长,企业希望利用IPVPN为他们提供一种经济的方法,将公司网络扩展到远程站点、远程工作人员和移动工作人员,同时要求VPN能提供与专线连接水平相同的安全性等性能。服务供应商则认为VPN可以为他们的数据服务系列产品添加新的业务模式,使供应商能够提供新的IP增值业务来增加收入。《Shasta IP VPN业务及案例分析》一文介绍了北电网络Shasta 5000 BSN如何实现通用IP VPN,并使服务供应商能够通过先进的IP业务来实现他们与众不同的IP VPN。     

隧道通信技术介绍

隧道通信技术的出现解决了许多实际的网络通信问题．如移动IP中的移动性管理问题、不同IPv6网络通过IPv4网络互连、GPRS(分组无线业务)骨干网中GSN(GPRS支持节点)间的用户数据和信令传输等，展示了广泛的应用前景。隧道通信技术也是实现虚拟专用网(VPN)的关键技术。因此，我们有必要了解和掌握。     

BGP／MPLS VPN的嵌套

鉴于MPLS技术对IP数据传送的安全性、较强的流量工程能力，和对业务灵活针对性的QoS保证能力，目前各个运营商的IP网络逐渐采用MPLS技术搭建。这时，基于MPLS技术的VPN服务，逐渐成为实现IP VPN业务的主流技术。     

适合NGN的VPN承载平台的构建和应用推进

MPLS VPN是一种基于MPLS技术的IP VPN,是在网络路由和交换设备上应用MPLS技术、简化核心路由器的路由选择方式,是结合传统路由技术和标记交换实现的IP虚拟专用网络,可用来构造宽带的Intranet和Extranet,满足多种灵活的业务需求。MPLS VPN技术可以把现有的IP网络分解成逻辑上隔离的网络,这种网络的应用是非常丰富的：可以解决企业互连、政府要构互连的问题,也可以用来提供新的业务(如为IP电话业务专     

爱立信端到端优化服务：GPRS数据业务的倍增器

GPRS业务是对现有GSM网络业务的补充，它引进了数据传输业务，使得用户可在移动环境里永远在线。终端用户可以始终在线，接收电子邮件和享受其它服务，而只为收到的信息进行付费，其余的在线时间则免费。通过增加新的数据业务节点和升级现有节点，就可在移动终端和外部网络之间提供GPRS业务。开发GSM网的GPRS功能，可使运营商在节省资源的前提下让用户接入基于IP的外部网络。数据交     

一种新的移动IP与GPRS的融合方案

IETF制定的移动IPV4标准是一种在基于IP的网络上提供通用移动功能的方案，它可以使终端在不改变其IP地址的前提下，通过不同的接入网接入基于IP的网络。为了使GPRS系统也支持移动IPV4功能，3GPP提出了一种解决方案。该方案的主要缺陷是对现有GPRS规范改动较大，且改变了GGSN的功能定位，不利于系统的平滑升级，本文提出了一种新的实用的移动IPV4与GPRS的融合方案，特点是在不改变GPRS体系结构和移动IP结构框架的基础上，通过改进GPRS相关参数的配置以及SGSN选择GGSN的算法，实现移动IPV4与GPRS的融合，测试表明，通过该方案，使GPRS不仅可以支持标准IP业务，而且也支持移动IP业务。     

基于GPRS的VPN技术

虚拟专用网(VPN)是一种在公共网络资源上实现专用通信的技术,它可以将物理上分散的分支机构连接在一起,从而有效地实现办公一体化、电子商务等。目前最常见的是基于ChinaNet的VPN,这种VPN使用普通电话线、专线等作为通信线路,其缺点是用户不能随意漫游、移动。通用分组无线业务(GPRS)网络首次将移动通信与因特网联系起来,为用户提供无线上网服务。在GPRS网络上开展VPN可以实现移动虚拟专用网,这样用户通过笔记本电脑和GPRS手机就可以随时随地接入到自己的VPN中,从而很方便地进行办公、商务等。通过GPRS实现VPN极大地扩展了V…     

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.