ect the customer to the network- come in a variety of forms and offer a broad variety of connectivity options and bandwidth levels. The key to success is to not be a bottleneck; access technologies that can evolve to meet the growing customer demands for bandwidth will be the winners in the game. DSL holds an advantage as long as it can overcome the availability challenge and the technology challenge of loop carrier restrictions. Wireless is hobbled by licensing and spectrum availability, both of which are regulatory and legal in nature, rather than technological limitations. In the next chapter, we will discuss transport technologies including private-line, frame-relay, ATM, and optical networking. Chapter 6 Questions Is wireless an access or a transport technology? "A 56 Kbps modem is not really a 56 Kbps modem." Explain. Why is ISDN not a more popular technology in the United States? Explain the differences between a BRI and a PRI. "DSL is actually an analog technology." Explain. Explain the purpose of a DSLAM. What are the key differences between ADSL and ADSL2+? Why is the cable industry a far greater threat to the ILECs than the CLECs? Who uses LMDS and MMDS today? What are the differences between FDMA, TDMA, and CDMA? Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. CHAPTER Transport Technologies Transport Technologies Chapter 7 We have now discussed the premises environment and access technolo- gies. The next area we'll examine is transport. Because businesses are rarely housed in a single building, and because their customers are typically scattered across a broad geo- graphical area (particularly multinational customers), there is a growing need for high-speed, reliable, wide-area transport. "Wide-area" can take on a variety of meanings: For example, a company with multiple offices scattered across the metropolitan expanse of a larg