1 / 16

Session 9

Session 9. Data Communications and Cable Communications . Session Objectives. Midterm Returned Review, Session 8 - Network Services Data communications Cable communications High-definition television formats. Review, Session 8. How does a virtual network differ from a private network?

corby
Download Presentation

Session 9

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Session 9 Data Communications and Cable Communications Session 9 - Data and Cable Communications

  2. Session Objectives • Midterm Returned • Review, Session 8 - Network Services • Data communications • Cable communications • High-definition television formats Session 9 - Data and Cable Communications

  3. Review, Session 8 • How does a virtual network differ from a private network? • Compare DSL with ISDN as to information rate, flexibility, cost, and current availability. • How many links are required for an n-node star network? For an n-node full mesh? What does the result imply as to cost and reliability? • Explain how Common Channel Interoffice Signaling provides performance and cost gains. Session 9 - Data and Cable Communications

  4. Review for Session 8 (cont.) • Identify some of the subscriber services that SS7 makes possible. • Briefly explain “voice and data convergence” and its significance for telecommunications performance and cost. • What are advantages and disadvantages of ATM’s fixed, 53-byte cell size? Session 9 - Data and Cable Communications

  5. Data Circuit-Termination Equipment (DCE) • Terminates a network data circuit and interfaces with data terminal equipment (DTE) • Examples • Modem (plain, FAX, PCMCIA) • NT1 (for ISDN) • Channel Service Unit/Data Service Unit • Cable modems Session 9 - Data and Cable Communications

  6. DCE Functions • Analog-digital conversion • Maintaining required voltage levels • Synch • Error detection • Buffering • Compression • Testing point for network Session 9 - Data and Cable Communications

  7. Hybrid Fiber-Coax Architecture Session 9 - Data and Cable Communications

  8. Cable Modems • High interest; cf. AT&T-TCI merger • No standard yet • Functions • Interface to upstream and downstream channels • Analog-digital conversion, as before • Modulation of cable RF carrier with encoded data (as contrasted with baseband transmission of the data) • Demodulation of cable RF carrier to recover data • Filter packet addresses Session 9 - Data and Cable Communications

  9. Cable Pro’s Broadband Entertainment content Cable Con’s Small region coverage No switching experience Poor reliability Limited billing systems Meager R&D Scarce cash Poor reputation Telephone Con’s Narrowband No content origination Telephone Pro’s Large region coverage Switching competence Reliability Great billing experience Massive R&D Deep pockets Brand name recognition Large customer base Cable vs. Telephone Session 9 - Data and Cable Communications

  10. Title VI--Cable Communications • Sec. 601. Purposes • Establish franchise standards • Establish regulation guidelines • Establish protection for franchise renewal • Assure diversity • Promote competition • Sec. 611. May require channels for public, educational, and government (PEG) use Session 9 - Data and Cable Communications

  11. Title VI--Cable Communications (cont.) • Sec. 612. Must provide some channels for competitive commercial use • Sec. 613. Media cross-ownership allowed • Sec. 614. “Must carry” at least some local stations • Under election of right to carriage (Sec. 325.), or • Station’s “retransmission consent” (implies payment) • Sec. 615. Must carry noncommercial educational television Session 9 - Data and Cable Communications

  12. Title VI--Cable Communications (cont.) • Sec. 621. No exclusive franchises • Sec. 623. No regulation where effective competition exists; otherwise, regulates “basic tier” and unreasonable rates • Sec. 624A. TV, VCR, and cable compatibility • Sec. 629. Set-top boxes competitively available • Sec. 639. No obscene programming • Sec. 641. Scramble adult videos Session 9 - Data and Cable Communications

  13. Video Provisions (1996 Act) • Sec. 651. Video programming • As common carrier, or • As a cable system, or • As open video system • Sec. 652. No cable or telephone buy outs above 10% • Sec. 653. Open video systems • No discrimination • No hogging the system • Sec. 302 (1996 Act). No new video dialtone Session 9 - Data and Cable Communications

  14. Digital TV and Analog TV Comparisons • Analog TV Characteristics • 6 MHz analog signal carries intensity and color info • 525 scan lines by 500 pixels per line (262,500 pixels) • 1/60 sec. Interlaced (refreshed image every 1/30 sec.) • Digital TV (DTV) Characteristics • 6 MHz compressed digital signal carries increased detail and high quality Dolby Digital Surround sound • 720 scan lines by 1080 pixels (777,600 pixels) • 1/60 sec. Interlaced and Progressive Frame Rates Session 9 - Data and Cable Communications

  15. HDTV Video Graphics Array (VGA) Formats • Formats Used in HDTV • 480i = 640x480 pixels interlaced • 480p = 640x480 pixels progressive • 720p = 1280x720 pixels progressive • 1080i = 1920x1080 pixels interlaced • Scanning System Formats • Interlaced Format, 1/60 sec. (1/30 sec. image refresh) • Progressive Format, 1/60 sec. whole image refresh • Interlaced has flicker and Progressive uses bandwidth Session 9 - Data and Cable Communications

  16. Digital TV Scanning Formats Session 9 - Data and Cable Communications

More Related