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Using Telephone and Cable Networks for Data Transmission

Using Telephone and Cable Networks for Data Transmission. Semester: 131 Course: CSET 221 Computer Networking Instructor: Farhan Khan Computer Science & Engineering Technology Unit Hafr Al-Batin Community College. Outline. Telephone lines Dial-up modems Digital Subscriber Line (DSL)

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Using Telephone and Cable Networks for Data Transmission

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  1. Using Telephone and Cable Networks for Data Transmission Semester: 131 Course: CSET 221 Computer Networking Instructor: Farhan Khan Computer Science & Engineering Technology Unit Hafr Al-Batin Community College

  2. Outline • Telephone lines • Dial-up modems • Digital Subscriber Line (DSL) • Cable TV networks

  3. Telephone Lines • Traditional telephone lines can carry frequencies between 300 and 3300 Hz • Giving them a bandwidth of 3000 Hz • All this range is used for transmitting voice • A great deal of interference and distortion can be accepted without loss of intelligibility

  4. Telephone Line Bandwidth

  5. Dial-Up Modems Modem stands for modulator/demodulator.

  6. 56K Modems

  7. Digital Subscriber Line (DSL) After traditional modems reached their peak data rate, telephone companies developed another technology, DSL, to provide higher-speed access to the Internet. Digital subscriber line (DSL) technology is one of the most promising for supporting high-speed digital communication over the existing local loops. Topics discussed in this section: ADSL ADSL Lite HDSL SDSLVDSL

  8. Digital Subscriber Line (DSL) • Provides higher-speed access to the Internet • Supports high-speed digital communication over the existing local loops • The existing local loops can handle bandwidths up to 1.1 MHz

  9. ADSL • ADSL – Asymmetric Digital Subscriber Line • Downstream bit rate > upstream bit rate • Designed for residential users • Unsuitable for businesses • ADSL operates on existing local loops • Local loops can handle up to 1.1 MHz of bandwidth • The distance limit is ~18,000 feet • The system uses a data rate based on the condition of the local loop line

  10. ADSL is an asymmetric communication technology designed for residential users; it is not suitable for businesses.

  11. The existing local loops can handle bandwidths up to 1.1 MHz

  12. ADSL is an adaptive technology. The system uses a data rate based on the condition of the local loop line.

  13. Bandwidth Division in ADSL

  14. Discrete Multi-Tone Modulation • Or DMT

  15. Bandwidth Division 4Khz Allocation and modulation of each channel are determined adaptively

  16. Bandwidth Division • Voice – Channel 0 • Idle – Channels 1-5 • Upstream – Channels 6-30 • 24 data channels, 1 control channel • 1.44 Mbps (max) upstream bit rate • Actual bit rate: 64 Kbps to 1 Mbps • Downstream – Channels 31-255 • 224 data channels, 1 control channel • 13.4 Mbps (max) downstream bit rate • Actual bit rate: 500 Kbps to 8 Mbps

  17. ADSL Customer Residence

  18. DSL Access Multiplexer • Or DSLAM

  19. Other DSL Technologies • HDSL – High-bit-rate DSL • SDSL – Symmetric DSL • VDSL – Very-high-bit-rate DSL • ADSL2 • ADSL2+ • See also • http://en.wikipedia.org/wiki/Digital_subscriber_line Source: AWARE. ADSL2 and ADSL2+ The new ADSL standard.

  20. Table 9.1 Summary of DSL technologies

  21. Cable TV Networks The cable TV network started as a video service provider, but it has moved to the business of Internet access. In this section, we discuss cable TV networks; in next Section we discuss how this network can be used to provide high-speed access to the Internet. Topics discussed in this section: Traditional Cable Networks HybridFiber-Coaxial (HFC) Network

  22. Cable TV Networks • Started as a video service provider, then moved to the business of Internet access Communication is simplex

  23. Communication in the traditional cable TV network is unidirectional.

  24. Hybrid Fiber-Coaxial Network • Or HFC • Bidirectional communication is achieved

  25. Communication in an HFC cable TV network can be bidirectional.

  26. Cable TV for Data Transfer Cable companies are now competing with telephone companies for the residential customer who wants high-speed data transfer. In this section, we briefly discuss this technology. Topics discussed in this section: Bandwidth CM and CMTS

  27. Division of Coaxial Cable Band by CATV • Downstream Video Band can accommodate more than 80 channels. • Each TV channel occupies 6 MHz • Theoretical downstream data rate is 30 Mbps • Theoretical upstream data rate is 12 Mbps

  28. Downstream data are modulated using the QAM modulation technique.

  29. The theoretical downstream data rateis 30 Mbps.

  30. Note Upstream data are modulated using the QPSK modulation technique.

  31. The theoretical upstream data rate is 12 Mbps.

  32. Cable Modem (CM)

  33. Cable Modem Transmission System • Or CMTS

  34. Summary • Telephone lines • Dial-up modems • Digital Subscriber Line (DSL) • Cable TV networks

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