第7章_通信网络与无线技术祥解.ppt

参考资料 Kenneth C. Laudon, Jane P. Laudon. Management Information Systems: managing the digital firm, 9th Edition Pearson - Prentice Hall, New Jersey, 2006 肯尼斯. 劳顿，简. 劳顿 箸. 薛华成 编译. 管理信息系统. 北京：机械工业出版社，2011. Challenge: Outdated networking environment, high maintenance costs, and poor service to 19 schools and 8,000 students Solutions: Install a TCP/IP networking environment that handles both voice and data traffic, and supports intranet for teachers Standardize desktop operating systems and hardware Illustrates the importance of using Internet-based networking technologies to achieve business and service goals This graphic illustrates the three main topologies in use in LANs. In a star topology, all devices on the network connect to a single hub and all network traffic flows through the hub. In an extended star network, multiple layers or hubs are organized into a hierarchy. In a bus topology, one station transmits signals, which travel in both directions along a single transmission segment. All of the signals are broadcast in both directions to the entire network. All machines on the network receive the same signals, and software installed on the client’s enables each client to listen for messages addressed specifically to it. A ring topology connects network components in a closed loop. Messages pass from computer to computer in only one direction around the loop, and only one station at a time may transmit. The ring topology is primarily found in older LANs using Token Ring networking software. Ask students which of the topologies is the most common. * This slide looks at the media involved in network transmission. Note that many of the telephone systems in buildings had twisted wires installed for analog communication, but they can be used for digital communication as well. Also, today, telecommunications companies are starting to bring fiber optic cable into the home for high-speed Internet access. Ask students what characteristic of microwave transmission m