• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
Overview of the public switched telecommunications network (pstn)

Overview of the public switched telecommunications network (pstn)






Total Views
Views on SlideShare
Embed Views



1 Embed 4

http://www.slideshare.net 4



Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
Post Comment
Edit your comment
  • The PSTN was designed to carry voice traffic. PSTN engineered to deliver service level consistent with the demands of voice communications. The PSTN was designed to deliver: Limited bandwidth (a “voice channel”). Low latency (no network-induced delay). Network “blocked” access if these conditions could not be met. PSTN could provide more than voice services. Fax and low-speed data ultimately were delivered over the same “voice” network. Reliable due to battery back-up.

Overview of the public switched telecommunications network (pstn) Overview of the public switched telecommunications network (pstn) Presentation Transcript

  • Presented by Trevor R. Roycroft, Ph.D. 2008 NASUCA Annual Meeting. November 17, 2008 Roycroft Consulting Economic and Policy Analysis [email_address] www.roycroftconsulting.org 508-896-0151
    • AT&T Bell system built a “nationwide” network to provide local and long distance services.
    • A “public switched” telecommunications network (PSTN).
    • Provided services at regulated rates on a “common carriage” basis.
    • Universal Service.
      • Network capabilities similar nationwide.
  • Distribution And Drop (Copper Twisted Pair) Feeder Copper or Fiber “ Local Loop” Local Switch Tandem Switch Local Transport Copper or Fiber “ Long Distance” Network (Fiber) Mobile Telephone Switching Office “ Long Distance” Network (Fiber) Legacy PSTN Technology Deployment
    • The Internet revolution.
    • Internet technology introduces:
      • Packet switching.
      • A standardized communication platform, delivering “best effort service.”
        • No blocking.
        • Transmission latency possible.
      • Potential for high bandwidth demand.
    • How will the change affect the PSTN?
    • Section 706 of the 1996 Act states:
      • The Commission and each State commission with regulatory jurisdiction over telecommunications services shall encourage the deployment on a reasonable and timely basis of advanced telecommunications capability to all Americans.
        • “ advanced telecommunications capability' is defined, without regard to any transmission media or technology, as high-speed, switched, broadband telecommunications capability that enables users to originate and receive high-quality voice, data, graphics, and video telecommunications using any technology.”
    • Competing platforms
      • Cable
      • Telephone company
        • RBOCs stick to their own turf.
      • Overbuilders
      • Wireless
        • RBOCs own largest wireless providers
        • AT&T and Verizon purchased majority of 700 MHz spectrum
        • WiMax on horizon?
    • Will competition ensure affordability?
    • Will competition ensure universal access/service?
    • Will competition deliver end-to-end compatible technologies?
      • Encourage benefits of network effects.
  • Downstream Upstream FTTH VDSL2 Cable Modem (DOCSIS 3.0) Cable Modem (DOCSIS 2.0) ADSL2+ WiMax Basic DSL
    • Voice over Internet Protocol
      • Relies on packet switching approach.
    • Uses broadband access network.
    • Within the broadband access network, the relative position of voice has changed.
      • IPTV customer—200+ Gigabytes per month.
      • Voice customer—less than 1 Gigabyte per month.
    • Largest telephone company.
      • 35 million residential subscribers in 21 states.
      • 75 million wireless subscribers.
      • Have used DSL to deliver broadband.
    • “ Fiber to the neighborhood” (FTTN).
    • Utilizes existing copper distribution network.
    • Shortens the copper run.
      • Typically enables 25 Mbps downstream, 1-3 Mbps upstream.
      • Majority of bandwidth devoted to provision of U-verse television.
    • “ IPTV” is used to compensate for limited overall bandwidth.
  • Copper Fiber replaces Copper Local Loop Overhaul (FTTN) Node Set-Top Box Residential Gateway Household Phone Company Central Office FTTN pushes fiber deeper into the neighborhood to shorten the copper runs to 3,000 to 5,000 feet.
  • IP Video Hub Offices National IP Backbone IP Video Super Hub IP Serving Offices Copper Fiber Fiber Greenfield FTTP Local Loop Overhaul (FTTN) Node Set-Top Box Residential Gateway Household Household
    • Low-bandwidth for data.
    • Fiber deployments appear to be constrained for marketing purposes to copper performance.
    • “ Pair-bonding” may double the capacity available, but delivery of HD programming may command most of this additional bandwidth.
    • Competitive pressure on cable systems, which already beat U-verse Internet bandwidth with existing platform?
    • Structural discrimination against non-U-verse video?
    • About 780,000 subscribers nationwide.
    • 14 Million living units passed as of 3 rd Quarter 2008.
    • Second largest telephone company.
      • 24.5 million residential subscribers in 29 states.
      • 68 million wireless subscribers.
      • Use both DSL and selective deployments of fiber to the home (FTTH).
    • FTTH provides a direct fiber optic connection to the home.
      • Replaces the copper wires in the network.
  • FiOS Optical Network Terminal Optical Line Terminal Optical Couplers (WDM) Voice & Data Downstream 1490 nm Upstream 1310 nm Voice, Data & Video 1490 nm, 1310 nm, 1550 nm 1x32 Optical Splitter Video 1550 nm CENTRAL OFFICE CUSTOMER PREMISE PSTN Verizon IP Network Internet Video Hub
    • About 1.6 million FiOS TV customers nationwide.
    • About 2.2 million FiOS Internet customers nationwide.
    • Projects passing 12 million homes by year-end 2008.
    • Preferred technology, but limited to portions of Verizon’s service area.
  • (1-year agreement) Plans FiOS with existing Verizon phone service FiOS without Verizon phone service   Up to 10 Mbps/2 Mbps $42.99/month $47.99/month Up to 20 Mbps/5 Mbps $52.99/month $57.99/month Up to 20 Mbps/20 Mbps $64.99/month $69.99/month $139.95/month $144.95/month Up to 50 Mbps/20 Mbps
    • Qwest has announced plans for a limited FTTN deployment.
      • To pass 1.5 million homes by year-end 2008.
      • Mixed signals regarding video plans.
    • Will competition ensure affordability?
      • Voice prices
      • Broadband Internet access.
    • Will competition ensure universal access/service?
      • AT&T v. Verizon v. Qwest
    • Will competition deliver end-to-end compatible technologies?
      • Bandwidth differences impact application development and innovation.
    • ILECs don’t have to unbundle fiber.
    • Copper retirement.
      • Strips a technology platform from the network.
        • DSL
        • Ethernet over copper.
  • USA