Wide Area Networks Answers Part 1

Chapter 9 Wide Area Networks True-False Questions The following are possible True/False questions for tests. The statement is given and the answer provided. The level of difficulty (easy, medium, hard), the reference section relevant to the topic, and learning objective are also furnished. 1. In constructing Wide Area Networks, many organizations do not build their own long distance communication circuits. Answer: True 2. WANs can connect BNs across distances that can span up to thousands of miles. Answer: True 3. Common carriers sell or lease communication services and facilities to the public. Answer: True 4. A common carrier that provides long distance services is typically called a local exchange carrier. Answer: False 5. A dedicated circuit is usually not available late at nights or on weekends. Answer: False 6. A WAN with a ring topology can use full or half-duplex circuits Answer: True 7. A disadvantage of a star architecture is that the failure of one circuit will disrupt the entire network. Answer: False 8. Full mesh networks are inexpensive. Answer: False 9. Full mesh design networks are more common than partial mesh design networks. Answer: False 10. T carrier circuits can only be used to transmit voice. Answer: False 11. A T1 circuit provides a data rate of 1.544Mbps. Answer: True 12. SONET is made up of high-speed dedicated circuits that incorporate inverse multiplexing (IMUX) for all levels above the OC-1 level. Answer: True 13. An OC-1 circuit provides a data rate of 155 Mbps. Answer: False 14. To connect into a packet switched network, a network terminator is generally used. Answer: False 15. Packet switched networks enable packets from separate messages or separate organizations to be interleaved for transmission. Answer: True 16. Datagrams are connection-oriented. Answer: False 17. The committed information rate (CIR) in a permanent virtual circuit is the maximum allowable rate that the network will attempt to provide. Answer: False 18. Frame relay is a reliable packet service. Answer: False 19. Ethernet services are now being successfully used in WAN environments. Answer: True 20. Virtual private networks permit users to create permanent virtual circuits, or tunnels, through the Internet. Answer: True 21. MPLS operate at layer 4. Answer: False 22. VPNs offer high security because they operate through the Internet. Answer: False 23. An intranet VPN connects different organizations over the Internet. Answer: False 24. The market for WAN services has declined dramatically over the past few years. Answer: False 25. Most common carriers charge per packet. Answer: False 26. Frame relay is no longer available. Answer: False 27. Multiprotocol label switching (MPLS) is a technology that is classified within the 5-layer network model. Answer: False 28. The Ethernet circuit data rate is fixed and cannot be changed. Answer: False 29. Virtual private network (VPN) services are much more expensive than dedicated circuit or packet-switched services. Answer: False MULTIPLE CHOICE The following are possible multiple-choice questions for tests. The question is posed and the answer is provided under the choices. The level of difficulty (easy, medium, and hard) and the page number(s) relevant to the topic is also furnished. 1. ____________ are companies that build a data and telecommunications infrastructure from which other companies can lease services for WANs and MANs. a. b. c. d. e. Common carriers Router manufacturers Standards organizations CSUs PUCs Answer: a 2. Each state or Canadian province has its own ___________ to regulate communications within its borders. a. b. c. d. e. CRTC Federal Communications Commission common carriers public utilities commission PTT Answer: d 3. The _________________ is a United States government agency that regulates voice and data communication. a. b. c. d. e. PSTN FCC CRTC CSU POTS Answer: b 4. A ___________ is a device that permits a customer to connect to a digital T-carrier service. a. b. c. d. e. modem codec CSU/DSU NIC ATM Answer: c 5. Which of the following is not a basic architecture for dedicated circuit networks? a. b. c. d. e. ring partial mesh bus star full mesh Answer: c 6. A ________ geometric layout connects all computers in a closed loop, with each computer linked to the next usually with a series of point-to-point dedicated circuits. a. b. c. d. e. bus design star design full mesh design ring design partial mesh design Answer: d 7. In a ring architecture WAN, a. b. c. d. messages can take a long time to travel from the sender to the receiver a message arrives at all computers on the network simultaneously messages always arrive faster than in other types of layouts messages are delivered directly from sender to receiver because there is a pointto-point connection directly between each sender and each receiver e. messages always take one second to travel between sender and receiver Answer: a 8. In a ring architecture WAN, a. b. c. d. failure in one circuit means that the network can most likely continue to function failure in one circuit always means that the network will cease to function failure in one computer always means that the network will cease to function failure in one circuit means that there will not be any increased traffic delays in the network e. failure in one computer always means that messages will stop at that computer since it would be impossible to re-route traffic Answer: a 9. A star architecture: a. connects all computers in a closed loop b. connects all computers off a backbone circuit c. connects all computers to one central computer that routes messages to the appropriate computer d. all of the above e. none of the above Answer: c 10. A _______ geometric layout for a WAN connects all computers to one central computer that routes messages to the appropriate computer, usually via a series of point-to-point dedicated circuits. a. b. c. d. e. ring design mesh design bus design star design mesh design Answer: d 11. A star topology is: a. difficult to manage because the central computer receives and routes all messages in the network b. dependent upon the capacity of the central computer for its performance c. always slower than a ring network d. less susceptible to traffic problems than other architectures e. not affected if the central computer fails Answer: b