网络课件networksch01a.pptVIP

第一章 概述 计算机网络的历史和新进展 Internet History and Growth Use of networks and network hardware 计算机网络体系结构 Part Ⅰ计算机网络技术的历史和新进展 高速计算机信息网络是信息社会的神经和血管 体系结构：网络的骨架和神经 协议：网络的心脏和血液 主要内容 网络概述 Internet的发展和成功经验 计算机网络技术的历史回顾 国际高速计算机网络研究计划 中国高速计算机网络研究计划 What is a Network?from end system point of view Network offers a service: move information bird, fire, messenger, truck, telegraph, telephone, Internet … another example, transportation service: move objects horse, train, truck, airplane ... What distinguish different types of networks? The services they provide What distinguish the services? latency bandwidth loss rate number of end systems service interface (how to invoke?) other details reliability, unicast vs. multicast, real-time, message vs. byte ... What is a Network?Infrastructure Centric View Electrons and photons as communication medium Links: fiber, copper, satellite, … Switches: mechanical/electronic/optical, crossbar/Banyan Protocols: TCP/IP, ATM, MPLS, SONET, Ethernet, PPP, X.25, FrameRelay, AppleTalk, IPX, SNA Functionalities: routing, error control, congestion control, Quality of Service (QoS) Applications: FTP, WEB, X windows, ... Types of Networks Geographical distance Local Area Networks (LAN): Ethernet, Token ring, FDDI Metropolitan Area Networks (MAN): DQDB, SMDS Wide Area Networks (WAN): X.25, ATM, frame relay Information type data networks vs. telecommunication networks Application type special purpose networks: airline reservation network, banking network, credit card network, telephony general purpose network: Internet Types of Networks Right to use private: enterprise networks public: telephony network, Internet Ownership of protocols proprietary: SNA open: IP Technologies terrestrial vs. satellite wired vs. wireless Protocols IP, AppleTalk, SNA 计算机网络发展历史回顾 七十年代的计算机网络 X.25 分组交换网：各国的电信部门建设运行 各种专用的网络体系结构：SNA，DNA Internet 的前身ARPANET进行实验运行 八十年代的计算机网络 标准化计算机网络体系结构：OSI 局域网络 LAN 技术空前发展 建成NSFNET，Internet 初具规模 九十年代的计算机网络 Internet空前发展 Web技术在Internet/Intranet 得到广泛应