1. Chi-Cheng Lin, Winona State University CS 313 Introduction to Computer Networking & Telecommunication DSL and Cable

2. 2 Topics l Digital Subscriber Line l Cable l ADSL versus Cable

3. 3 Digital Subscriber Lines l Bandwidth versus distanced over category 3 UTP for DSL.

4. 4 Digital Subscriber Lines l Operation of ADSL using discrete multitone modulation (OFDM, actually) - Channels – 0: voice, 1-5: not used, 6-30 upstream, 31-255 downstream - Each channel: QAM at the rate of 4000 baud, 0-15 bits/symbol depending on SNR - Multiplexing: FDM? TDM? Both? None?

5. 5 Digital Subscriber Lines l A typical ADSL equipment configuration.

6. 6 Cable Television l Community Antenna Television l Internet over Cable l Spectrum Allocation l Cable Modems

7. 7 Community Antenna Television l An early cable television system.

8. 8 Internet over Cable l Cable television

9. 9 Compared to Telephone System l The fixed telephone system.

10. 10 Spectrum Allocation l Frequency allocation in a typical cable TV system used for Internet access

11. 11 Cable Modems l Typical details of the upstream and downstream channels in North America. - Three lights on the cable modem when it’s on … - 6-8 MHz channels  36 Mbps w/ QAM-64  27 Mbps w/ overhead subtracted - Multiplexing: FDM? TDM? Both? None? Anything else?

12. 12 ADSL versus Cable l Discussions …  Bandwidth capacity  Availability  Security  Reliability