计算机英语专业外语第三版unit9.doc

幻灯片1 UNIT 9 The Internet Section A The Internet 幻灯片2 The Internet —Introduction The most notable example of an internet is the Internet (note the uppercase I ), which originated from research projects going back to the early 1960s. The goal was to develop the ability to link a variety 0f computer networks so that they could function as a connected system that would not be disrupted by local disasters. 最著名的互联网例子是因特网（Internet，注意大写的Ｉ）。因特网起源于20世纪60年代初的研究项目。其目标是发展一种能力，将各种计算机网络连接起来，使它们能够作为一个不会因局部灾难而瓦解的互联系统运行。 幻灯片3 The Internet —Introduction Most of this original work was sponsored by the U.S. government through the Defense Advanced Research Projects Agency (DARPA--pronounced DAR-pa), Over the years, the development of the Internet shifted from a defense project to an academic research project, and today it is largely a commercial undertaking that links a worldwide combination of WANs, MANs, and LANs involving millions of computers. 最初的工作大多是由美国政府通过国防部高级研究计划局（DARPA——读作“DAR-pa”）发起的。随着岁月的推移，因特网的开发从一个国防项目转变成一个学术研究项目。如今，它在很大程度上是一个商业项目，连接着全世界的广域网、城域网和局域网，涉及数百万台计算机。 幻灯片4 The Internet —Internet Architecture I. Internet Architecture Conceptually, the internet can be viewed as a collection of domains, each of which consists of a network or a relatively small internet operated by a single organization such as a university, company, or government agency. Each domain is an autonomous system that can be configured as the local authority desires. I. 因特网体系结构 从概念上说，因特网可以看作是域的集合。每个域由一个网络或一个相对较小的互联网组成，由一个像大学、公司或政府机构那样的组织负责运行。每个域是一个自主系统，可根据本地管理机构的愿望进行配置。 幻灯片5 The Internet — Internet Architecture It might consist of a single computer or a complex internet consisting of many LANs, MANs, and even WANs. The establishment of domains is overseen by the Internet Corporation for Assigned Names and Numbers (ICANN), 它可能由一台计算机或一个包含许多局域网、城域网、甚至广域网的复杂互联网组成. 域的建立由互联网名称与数字地址分配机构（ICANN）监管, 幻灯片6 The Internet —Internet Architecture which is a nonprofit corporation established t