基于SDN的互联网域间路由研究

互联网流量的爆发式增长,叠加互联网流量固有的突发性特点,使得网络流量不均衡现象日益加剧。传统BGP协议由于缺乏全网拓扑和全局流量观,只能遵循标准BGP选路原则,在解决流量调度和负载均衡方面存在不足。针对BGP协议存在的局限性,研发了基于RR+的互联网骨干网流量调度系统,并应用于ChinaNet骨干网的网内中继、网间互联出口、IDC出口等多个流量优化场景。更进一步地,提出了一种基于SDN的互联网域间路由架构,通过在域间控制器之间交换BGP路由,无需在域内和域间运行BGP协议,极大地简化了网络协议,并能够实现灵活的流量调度和负载均衡。     

电信级高可用率BGP/MPLS VPN网络部署与优化

BGP/MPLS VPN作为基于一种城域的VPN部署技术,发展成运营商VPN服务的跨域实现.本文从建设电信级BGP/MPLS VPN网络的实际出发,分析了跨AS实现方式,计算了网络可用率、并应用HSRP协议进行网络优化,确定优化后的目标网络达到了电信级高可用率的要求.     

融合SDN技术的IP承载网流量调度系统研究

随着互联网业务迅猛发展,IP承载网网络规模和业务流量呈跨越式增长,传统维护模式难以支撑网络运维需要。课题研究通过引入IGP/BGP路由协议监听分析技术,实现网络拓扑自动生成、业务路由端到端可视;利用Netflow技术实现流量流向实时可视;在实现路由及流量可视化的基础上,叠加SDN流量调度技术,自动监测链路拥塞,智能选路,自动进行策略仿真和下发。基于课题研究开发基于SDN架构的IP承载网流量调度系统,有效提升维护质量和效率,满足精细化运维的需要。     

基于SDN的网络调优及控制器北向接口探讨

先介绍基于SDN的新型运营商网络架构的三个层次,对南向接口和北向接口的使用进行说明;然后介绍SDN的流量调度,并具体阐述SDN架构和网络流量调度操作的原因;最后介绍基于SDN流量调度的两种类型及北向接口要求.     

关于运营商BGP邻居建立排障思路探讨

边界路由协议(BGP)是在各大运营商中广泛使用的一种域间路由协议,主要功能是在各个AS之间和AS内部之间交换网络路由的可达信息,如何保证BGP在网络中的稳定运行和故障后的快速恢复是城域网运营商在运维中需要面对的挑战和任务。文章通过作者在运营商多年来的丰富的经验,分析了BGP路由关系不稳定的原因和条件,给出了系统的解决BGP邻居关系稳定的思路和办法。     

基于拓扑分域的光电混合网络控制研究

文中提出了一种将电层网络拓扑分域化的光资源提供方式,利用该思想设计了一种基于胖树网络的光电混合网络组网方案,结合软件定义网络架构与OpenFlow协议,设计并实现了网络控制器的连接管理、拓扑管理、流量监测模块。为解决传统网络设备不支持OpenFlow协议的缺陷,开发了一套基于Open vSwitch的网络设备代理,实现了OpenFlow协议与私有协议的转换,从而实现网络的统一化控制。最后对设计的方案进行了组网实验,实验结果表明,该方案能够有效地实现光网络与电网络的融合与协同工作,减轻电网络设备的工作负荷,提升网络整体性能;基于软件定义架构的网络体现出了良好的可编程特性,并能够实现网络资源的虚拟化和灵活调度。     

BGP实现网络流量负载分担

BGP是一种自治系统间的动态路由协议,广泛应用于各大电信运营商的核心IP网,它的基本功能是在自治系统间自动交换无环路的路由信息。目前,BGP不仅仅在国家网、省网中使用,许多大型城域网也使用BGP接入省网。众所周知,在自治系统网络内部,通过静态路由或者OSPF等IGP动态路由协议,只要路由器拥有等Metric的多条到达同一网段的路由,路由器就会对到达该网段的流量按照路由链路进行负载分担。在运行BGP的对等自治系统的网络中,如果边界路由器接收到多条到达同一目标网络的BGP路由,BGP最佳路径算法将会选出一条最佳路由,并仅用此路由来…     

Carriers''''carriers结构的BGP/MPLS VPN解决方案

Carriers＇carriers的BGP/MPLS VPN是一种递归嵌套的VPN网络结构.在分析了现有IPv4网络中其实现方法与不足的基础上,利用BGP的权能属性及多协议扩展属性,提出了一种在IPv4/v6混合网络中,基于跨域Carriers＇carriers结构的BGP/MPLS VPN解决方案.该方案以在核心骨干网及VPN承载网络中增设路由反射器为思路,能够很好地解决各级VPN的路由学习及业务流转发.     

基于LACP的链路聚合测试方法研究和实践

基于LACP的链路聚合技术在电信运营商现网部署中被广泛应用,其不仅是一种廉价且有效增加链路带宽的方法,同时也是提高网络稳定性的一种方案.首先简要介绍了LACP的原理,分析了常见应用场景,提出了LACP实验室的验证解决方案,列举了关键参数和测试要点,最后运用网络测试仪进行协议和流量的模拟验证.     

BGP／MPLSVPN标准化进展

1999年3月，因特网任务工作组(IETF)发布了由Cisco公司提出的RFC2547，描述了一种运营商通过IP骨干网为用户提供虚拟专用网(VPN)业务的方法。该方法使用扩展的BGP(边界路由协议)作为通过运营商的骨干网分发VPN路由信息，使用多协议标记交换(MPLS)在VPN用户站点之间转发VPN流量。提出该方法的主要目的是为了运营商向企业提供企业网外包服务。这种方式对企业非常简单，同时对运营商是可扩展的和灵活的，在提供IP业务的同时提供VPN业务，从而增加收入。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.