IPv6 delay and loss performance evolution

Although packet delay and loss are two important parameters of the Internet performance, to the best of our knowledge, the evolution of large‐scale IPv6 delay and loss performance has previously not been studied. In this paper, we analyze more than 600 end‐to‐end IPv6 paths between about 26 testboxes of RIPE Network Coordination Centre over two years, and compare the delay and loss performance over time with their IPv4 counterparts. We present and discuss the measurement methodologies and show that IPv6 paths have a higher delay and loss than their IPv4 counterparts. The main reason for the worse performance stems from IPv6‐in‐IPv4 tunnels rather than from native IPv6 paths and such tunnels are still widely used today. Copyright © 2007 John Wiley & Sons, Ltd.     

互联网下会计信息系统内部控制研究

网络会计给企业带来利益的同时 ,也给企业内部控制带来新问题。讨论了建立适应互联网环境下会计信息系统的内部控制 ,其措施应基于企业内部和外部的组织与管理、系统开发及网络系统安全控制等方面的问题     

基于嵌入式以太网的异步电机矢量控制系统体系结构设计

为了实现异步电机现场控制与上层管理的无缝集成，提出在通用变频器一异步电动机调速系统的基础上，采用基于ARM7TDMI核的微控制器和以太网控制芯片，实现异步电机的网络化控制。详细介绍了该系统的体系结构设计方案。     

The Role of Network Topologies in the Optical Core of IP-over-WDM Networks with Static Wavelength Routing

In this paper, we present a performance analysis of network topologies for the optical core of IP-over-WDM networks with static wavelength routing. The performance analysis is focused on regular degree four topologies, and, for comparison purposes, degree three topologies are also considered. It is shown that the increase of the nodal degree from three (degree three topology with smallest diameter) to four (degree four topology with smallest diameter) improves the network performance if a larger number of wavelengths per link is available. However, the influence of wavelength interchange on the nodal degree gain is small. The performance of regular degree four topologies with smallest diameter is also compared with the performance of mesh–torus topologies (which are also degree four topologies), and it is shown that the blocking probability of degree four topologies with smallest diameter is about two orders of magnitude lower than the blocking probability of mesh–torus topologies. It is also presented a performance comparison of WDM-based networks with nodal degrees ranging from two to five and it is shown that the increase of the nodal degree from two to three leads to high nodal degree gains, while de increase of the nodal degree from four to five leads to low nodal degree gains. These results show that degree three and degree four topologies are very attractive for use in the optical core of IP-over-WDM networks.     

电子数据交换EDI

介绍了电子数据交换的概念、EDI系统的组成，阐述了传统交易模式与EDl交易模式的区别，分析了实现EDI的三项挂心技术，介绍了EDl与Internet的关系、实施EDI的效益以及EDI的应用与EDI的前景。     

基于面像识别技术的公安网上追逃系统

研究了公安网上追逃系统的体系结构和系统的程序流程，阐述了ASP COM 后台比对服务的3层B／S模式面像网上比对的实现方法，最后给出系统的性能指标和特点。     

互联网技术和国际互联网

本文先是说明internet、Internet和intranet各自的涵义和相互的区别 ,并简单介绍互联网的几项基本规约 ,包括IP、TCP、UDP、FTP、TFTP、SMTP和HTTP。其次说明WWW及其使用的超文本 /超媒体、浏览器和客户 /服务器技术的作用 ,解释Internet的骨干网和接入网以及内部网与防火墙。最后推测Internet的应用发展前景。     

网上电子银行系统

本文简要介绍网上电子银行系统的基本结构。重点讲述信息传送服务器 ,并给出该系统的设计例。     

Internet 防火墙及其发展趋势

本文叙述了Internet来自外部、内部、硬件、软件方面的十种安全威胁和攻击,给出了防火墙的限制、隔离、筛选、过滤和屏蔽作用,介绍了防火墙的六种基本结构类型,论述了过滤路由器、双宿主主机、主机过滤、过滤子网和吊带式五种安全结构,分析了传统防火墙的七种不足,给出了目前防火墙混合应用包过滤技术、代理服务技术和其他一些技术的发展趋势。     

智能小区中的网络和布线设计解决方案——智能建筑学术讨论系列文章之七

当前小区信息网络建设中存在多种实施方案。笔者分析比较了常用的几种典型方案的优劣。讨论了目前建设中的一些解决方法，提出了兼顾现状，适度超前的设计实施原则。