通信专业英语10.pptVIP

通信专业英语 Unit Ten Computer Communication---Network Part One A computer network is a system for communication among two or more computers. Network is a system that transmits any combination of voice, video and/or data between users. The network includes the network operating systems in the client and server machines, the cables connecting them and all supporting hardware in between such as bridges, routers, and switches. In wireless systems, antennas and towers are also part of the network. So are LAN, WAN, client, server, and enterprise networking etc. Two or more computers connected for the purpose of routing, managing, and storing rapidly changing data. A local area network (LAN), which is restricted by distances of up to one mile, and a metropolitan area network (MAN), which is restricted to distances of up to 60 miles, connect personal computers and workstations (each called a node) over dedicated, private communications links.A wide area network (WAN) connects large numbers of nodes over long-distance communications links, such as common carrier telephone lines, over distances ranging from that between major metropolitan centers to that between continents. An Internet is a connection been networks. The Internet is a WAN that connects thousands of disparate networks in the U.S., Canada, Europe, Asia, and elsewhere, providing global communications between nodes on government, educational, and industrial networks. Networks allow for resource sharing (e.g. multiple computers sharing one printer), data sharing, and communication or data exchange. One of the three principal topologies for a LAN, in which all nodes are connected to a central cable along which data is passed. Bus Network A network topology that uses a common pathway between all devices. Ethernet 10Base5 and 10Base2 are examples of bus networks. A bus work is a network architecture in which a set of clients are connected with a shared communications line, called a