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Who Will Use ATM and ADSL?

Who will use ATM and ADSL now?

Government

Health Industry

Finance

Manufacturing

Education

Home and Consumer Markets

ATM Service Today

ATM is currently available in the continental U.S., Canada, Western Europe, and Japan. Fifteen U.S. service providers are ramping up ATM services as fast as they can install switches and program back office systems to manage the backbone networks. ATM service today has these service characteristics:

  1. permanent virtual circuits
      virtual path connections
      virtual channel connections
  2. switched virtual circuits
  3. structured (DS-1) circuit emulation


    Figure 1-7.   continental perspective of global networks

  4. multiple platform/protocol interworking
  5. multiple service classes
  6. multiple interface rates
  7. multiple access interface speeds
  8. multiple service providers
  9. contract based pricing
  10. usage based billing

Application for Internet Services

The explosion in Internet growth and usage fuels the desire for higher data rates. Everyone tires of sluggish downloads, resulting in interminable waiting while images are slowly painted onto the screen. Additionally, the demand for Internet multimedia services including video services is a major driver.

Currently, several technologies exist to provide users with high-speed data access to the Internet. ISPs are frantically adding 56 Kbps analog modems to their access lines, assuming users will purchase the expensive analog modems also. Some users are connected to ISDN (Integrated Services Digital Network) and for an initial outlay of several thousands of dollars and a princely monthly sum can download data at either 64 Kbps or 128 Kbps, depending upon the class of service they have subscribed to (paid for). But 128 Kbps is still not fast enough for audio and video applications. Other users download Internet data via satellite at 400 Kbps for about $550 per month plus a capital equipment outlay of approximately $540. As fast as 400 Kbps seems, especially compared to the ubiquitous 9.6 Kbps and 14.4 Kbps analog modems, it is still not fast enough for audio and video applications even with the latest audio and video compression techniques. Audio in the context of this book means high quality, stereophonic audio.

ISPs currently depend upon POTS (Plain Old Telephone Service) to provide access to most homeowners and businesses. While some businesses and a few homeowners can afford ISDN and the attendant fiber cost, most Internet service is provided over copper wire. Internet service is limited by the speed of the analog modems hooked on each end of the transmission path between the user and ISP. The analog modems are limited by the 4 KHz audio bandwidth of the copper connection. Current analog modem technology data rates reach 56 Kbps and most industry engineers agree that 56 Kbps is the upper limit of analog modem technology. 56 Kbps does not come close to providing the speed required for audio, video, and multimedia services.


Figure 1-8   Evolution of information systems technology

Application for Video

CATV companies have coaxial cables that have a bandwidth up to 900 MHz running into homes. But TV channels consume bandwidth at a fierce rate, allowing cable companies to carry a maximum of 141 program channels downstream (to the user). All CATV programming is provided over community coaxial delivery systems. In 1996, major CATV companies laid off thousands of employees and fought for rate increases in many of the communities they serve. The driver behind the layoffs and rate increases was the rising cost of maintaining the expensive, and aging, coaxial based delivery system.

ATM and ADSL will allow video services companies to provide more channels of video programming and still have bandwidth for other purposes, such as Internet access and upstream (from user to the service provider) communications without laying a single coaxial cable. All they need do is transmit their programming over Granny Bells humble copper wire.

Applications for LANs

Legacy local area networks (LANs) such as token ring, Ethernet, and token bus are speed limited to 10 Mbps. Due to the data rate restriction, applications requiring faster rates must utilize other technologies, limiting LANs to primarily data applications in networks that are not easily "networked." Multimedia applications typically are a combination of voice, video, and data. Due to the bandwidth needs of multimedia, they require higher data rates than legacy LANs can deliver. ATM meets the bandwidth needs of multimedia and can be implemented in LANs, wide area networks (WANs), metropolitan area networks (MANs), and global area networks (GANs).


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