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Computer Networking

广西医科大学. Computer Networking. 网络课件. 双语教学. 模拟实验. 计算机网络教研室. DI. 1. 2. 3. Chapter 13 Wide Area Network(WANs). The first section. Exercises. Online lecture. Chapter 13 Wide Area Network(WANs). LAN SECURITY:

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Computer Networking

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  1. 广西医科大学 ComputerNetworking 网络课件 双语教学 模拟实验 计算机网络教研室

  2. DI 1 2 3 Chapter 13 Wide Area Network(WANs) The first section Exercises Online lecture

  3. Chapter 13 • Wide Area Network(WANs) • LAN SECURITY: • Proxy Server– acts as an intermediary between the internet and net-equipped computers • Password policies • A sign-off policy • The encryption of data sent on a LAN or stored on servers • Regular backup of the server disks • Downloading • Scanning of viruses www.gxmu.edu.cn

  4. VIRTUAL PRIVATE NETWORKS (VPN) • Chapter 13 • Wide Area Network(WANs) www.gxmu.edu.cn

  5. Chapter 13 • Wide Area Network(WANs) A corporate VPN using the Internet www.gxmu.edu.cn

  6. Chapter 13 • Wide Area Network(WANs) HOME NETWORKING and COMPONENTS OF A HOME NETWORK Ethernet Wireless Networks Phone Line Networks Power Line Networks www.gxmu.edu.cn

  7. 课后习题 • Chapter 13 • Wide Area Network(WANs) 1. Which of the following routing techniques are used in WANs? （　　）. D × A、 dynamic routing × B、 distributed routing × C、 static routing D、 All of the above √ Reset Next Show Answer

  8. 课后习题 • Chapter 13 • Wide Area Network(WANs) 2. Delays in networks can come from（　　）. D × A、 propagation × B、 switching × C、 queuing D、 All of the above. √ Reset Next Show Answer

  9. 课后习题 • Chapter 13 • Wide Area Network(WANs) 3. Which of the following was developed to overcome the overhead of packet switching and provide more efficient data transmission? （　　） B × A、 X.25 √ B、 frame relay × C、 circuit switched systems × D、 RS-232 Reset Next Show Answer

  10. 课后习题 • Chapter 13 • Wide Area Network(WANs) 4. In the context of ATM, a cell is（　　）. C × A、 the geographic boundary of the network × B、 the boundary of the area in which voice traffic can be handled √ C、 a 53-byte transmission unit × D、 the place where the designer is kept for specifying an overly complex network design Reset Next Show Answer

  11. 课后习题 • Chapter 13 • Wide Area Network(WANs) 5. VPNs（　　）. D × A、 can handle traffic relatively securely × B、 can restrict outside packets from entering the VPN × C、 are usually quite cost effective D、 All of the above. √ Reset Next Show Answer

  12. 课后习题 • Chapter 13 • Wide Area Network(WANs) packets 1. A packet switching system breaks a message into ______ and sends each one through the network independently. Answer 2. Alternate _______ are important so that message traffic can continue to be sent through the network even when the primary route has failed or otherwise become unusable. routes Answer 3. Packet switching is a form of __________ because messages from different nodes are interspersed on a circuit at any point in time. multiplexing Answer

  13. 课后习题 • Chapter 13 • Wide Area Network(WANs) datagram 4. A _________ is a packet that contains its destination address and is handled independently by the network. Answer 5. A centralized router in a network represents a single point of _______ and if it fails the entire network may be down. failure Answer 6. __________ routing sends all messages to every node on the network. broadcast Answer

  14. 课后习题 • Chapter 13 • Wide Area Network(WANs) router 7. A _________ determines the best way to route to use when sending a message through a network and sends it on its way. Answer 8. ___________ can occur in a network when the message volume exceeds the capacity of a part of the network. congestion Answer 9. _________ can occur at a node when messages arrive faster than they can be forwarded or processed. queuing Answer

  15. 课后习题 • Chapter 13 • Wide Area Network(WANs) frame relay 10. A ____________ network divides a message into variable length frames for transmission through the network. Answer 11. A frame relay network has approximately __________ (how much) of the overhead of a basic packet switching network. one quarter Answer 12. Packet switching operates on lines of _____ speed. any Answer

  16. 课后习题 • Chapter 13 • Wide Area Network(WANs) high OR multi-megabit 13. Frame relay was designed to operate on _________________ speed lines. Answer 14. A high speed transmission service that an organization may want to consider using for establishing a MAN within a city, and which is based on optical fiber as the transmission medium is called ________. SONET Answer

  17. Chapter 13 • Wide Area Network(WANs) Thank You ! www.gxmu.edu.cn

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