Section 4.1: WAN Topologies

Learning Objectives

After completing this section, you should be able to

• describe a variety of enterprise-wide and WAN physical topologies, their uses, advantages, and disadvantages.

Tasks

• Study the WAN Topologies section in Chapter 7 of the TD textbook to find answers to the study questions.
• Complete hands-on Project 7-3.
• Complete Case Project 7-1.

Study Questions

You may want to use the Personal Study Space wiki to answer these questions, which may require some Internet research. You can also post comments and queries in the Unit 4 Forum.

1. What is a wide area network?
2. How do WAN topologies differ from LAN topologies?
3. What network devices are critical in building WANs?
4. What kind of network traffic cannot be carried by a WAN link?
5. What is a peer-to-peer WAN topology?
6. Where is the peer-to-peer WAN topology often used?
7. What are the advantages and disadvantages of dedicated circuits for WANs?
8. What is a ring WAN topology?
9. What are the advantages and disadvantages of a ring WAN compared with a peer-to-peer WAN?
10. What is a star WAN topology?
11. What are the advantages and disadvantages of a star WAN compared to other WAN topologies?
12. What is a mesh WAN topology?
13. What are the advantages and disadvantages of a mesh WAN compared to other WAN topologies?
14. What is a tiered WAN topology?
15. What are the advantages and disadvantages of a tiered WAN compared to other WAN topologies?
16. What is a WAN link?
17. What are the differences and similarities between WANs and LANs?
18. When might an organization need a WAN?
19. What is ATM (Asynchronous Transfer Mode)?
20. What does ATM specify? What makes ATM different from Ethernet and token ring?
21. How does ATM benefit from its fixed packet size?
22. How does a small packet size in ATM affect the potential throughput of ATM?
23. What are virtual circuits?
24. How does ATM benefit from using virtual circuits?
25. How can ATM logical topology be integrated with Ethernet or token ring networks?
26. What is PSTN?
27. How do you access a remote server via PSTN network?
28. What are the advantages and disadvantages of PSTN?
29. Why is the throughput of a PSTN connection limited?
30. What was the X.25 technology originally designed for?
31. What is the maximum throughput of X.25?
32. How does an X.25 connection work?
33. What is the relationship between X.25 and Frame Relay technology?
34. What is maximum throughput of frame relay technology?
35. How does a frame relay connection work?
36. What are switched virtual circuits and permanent switched circuits?
37. What is the committed information rate (CIR)?
38. What are the advantages and disadvantages of using frame relay?
39. What services was integrated service digital network (ISDN) designed to provide?
40. What are the differences between ISDN and PSTN?
41. What channels are all ISDN connections based on?
42. What are the bandwidth of B-channels and D-channels?
43. What kinds of ISDN connections are commonly found in North America?
44. What channels does the BRI ISDN connection have?
45. What channels does a PRI ISDN connection have?
46. What are the main features of B-ISDN?
47. How does an ISDN line connect to an analogue device?
48. How do ISDN lines usually terminate at customers' sites?
49. What are the advantages and disadvantages of using ISDN connections?
50. What are T-carriers?
51. What multiplexing technology does T-carrier transmission use?
52. What are the main features of a T1 circuit?
53. What networking devices are needed to set up a T1 WAN connection? How?
54. What is DSL? What are the main features of ADSL, HDSL and VDSL?
55. What network devices are needed for setting up an ADSL connection?
56. What does a DSLAM do?
57. How are coaxial cables used for data network? What devices are needed? How does it work?
58. Why do traditional cable TV companies have to upgrade their cables in order to provide Internet services through their cable?
59. What is HFC?
60. What are cable-drop and head-end?
61. What disadvantages may a cable-based Internet connection have compared to ADSL?
62. What was SONET technology originally developed for?
63. What makes SONET different from T-carriers?
64. How does SONET work?
65. What major factors do you need to consider when choosing a WAN?
66. What WAN technologies are available?
67. What are the major features of each WAN technology?
68. Which WAN technology offers the highest transmission speed?
69. Which is the least expensive WAN technology?
70. Which is the most reliable WAN technology?
71. What WAN technology is most popular in the market?
72. Which WAN technology would you choose for individual or unimportant transmissions?
73. Which WAN technology would you choose for mission-critical applications?
74. How do you secure your WAN?
75. What are the major security threats to WANs? How do you deal with these threats?
76. What are VPNs?
77. What are the advantages of using VPN to implement a WAN?
78. How security and privacy issues are addressed in VPN?
79. What does remote connectivity mean? How is it different from WAN?
80. In what situation is remote access to a LAN needed?
81. What methods can use to implement remote access?
82. How can you access a LAN through the Internet by using a Web browser?
83. What is dial-up networking?
84. What does Windows 2008 Server offer for remote access?
85. What other companies offer similar remote access technologies?
86. What are the SLIP and PPP protocols?
87. What are the differences between the two?
88. Why is PPP much more popular than SLIP?