ch1Introduction(1.1-1.3)中文辅助.ppt

Introduction（概述） Chapter 1 （第一章） Chapter goal: get context, overview, “feel” of networking more depth, detail later in course approach: descriptive use Internet as example 1.1 Uses of Computer Networks 1.1.1 Business Applications Why we need a computer network? 4 goals of setting up a computer network To end the tyranny of geography. To do with people To do business electronically with other companies To do business with consumers over the Internet 1.1.1 Business Applications A network with two clients and one server. 1.1.1 Business Applications The client-server model involves requests and replies. 1.1.2 Home Network Applications Access to remote information (访问远程信息) Person-to-person communication (个人与个人通信) Interactive entertainment (交互式娱乐) Electronic commerce (电子商务) 1.1.2 Home Network Applications Access to remote information Newspapers on-line（在线报纸） Digital library（数字图书馆） The relation of a person and a remote database (个人与远程数据库的关系) 1.1.2 Home Network Applications Person-to-person communication Instant message （即时消息） Chat room （聊天室） Newsgroups （新闻组） C/S model and P2P 1.1.2 Home Network Applications In peer-to-peer system there are no fixed clients and servers. 1.1.2 Home Network Applications There are 2 generation of peer-to-peer system(对等系统的发展经过了两代) 第一代：central database 中央数据库 第二代：peer-to-peer database对等数据库（P8） 其特点：不需要中央数据库；每个用户在本地维护自己的数据库，并且提供一个列表，包含邻近的、也属于该系统的成员。 1.1.2 Home Network Applications Legal application example (合法的应用) 第一代：central database 中央数据库 第二代：peer-to-peer database对等数据库（P8） Electronic crime Copyright law Another hot area:electronic gambling 源于计算机能够模拟很多事务 例子：老虎机、轮盘、二十一点 Other application: Telephone calls,video phone, internet radio Telelearning 1.1.2 Home Network Applications Interactive entertainment Video on demand （视频点播） Game playing （游戏） 词汇： Killer application ：杀手级应用 Live television ：直播 Audience ：观众 Quiz shows ：智力游戏 Contestant：对手 1.1.2 Home Network Applications Electronic commerce Home shopping （在家购物） Access to financial inst