数据教程课件Chapter 1 introduction to CSP.ppt

Chapter One Introduction to Communications, Standards and Protocols Introduction Who today has not used a computer network? Mass transit, interstate highways, 24-hour bankers, grocery stores, cable television, cell phones, businesses and schools, and retail outlets support some form of computer network The Language of Computer Networks Computer network – an interconnection of computers and computing equipment using either wires or radio waves over small or large geographic areas Local area network – networks that are small in geographic size spanning a room, floor, building, or campus The Language of Computer Networks Metropolitan area network – networks that serve an area of 1 to 30 miles, approximately the size of a typical city Wide area network – a large network that encompasses parts of states, multiple states, countries, and the world The Language of Computer Networks Personal area network – a network of a few meters, between wireless devices such as PDAs, laptops, and similar devices Voice network – a network that transmits telephone signals Data network – a network that transmits computer data The Language of Computer Networks Data communications – the transfer of digital or analog data using digital or analog signals Telecommunications – the study of telephones and the systems that transmit telephone signals Network management – the design, installation, and support of a network, including its hardware and software The Big Picture Networks are composed of many devices, including: Workstations (computers, telephones) Servers Network hubs and switches (bridges) Routers (LAN to WAN and WAN to WAN) Telephone switching gear Topologies Common Bus Topology Star Topology Ring Topology Fully Connected Topology Combined Topologies LAN Topologies Common Bus Topology Multipoint medium: contention Transmission propagates throughout medium Heard by all stations Need to identify target station Each station has unique address Full duplex connection between station and t