Broadband Integrated Services Digital Network

The narrowband ISDN ( narrowband ISDN or ISDN - S; . Engl Narrowband ISDN and N -ISDN) with 64 kbit / s per user channel should be expanded to a broadband network, the broadband ISDN or B -ISDN. The B -ISDN in its original conception came but not beyond pilot tests. These pilot experiments allowed the participants originally a data transfer rate of up to 155 Mbit / s, in a next step 622 Mbit / s were planned. The planned network topology of the B-ISDN would have also met the ISDN: central switches in a hierarchical star network with meshing. One of the original basic ideas was that also the growing traffic of ISDN should be transferred by means of concentrators and multiplexers in the B -ISDN.

Among the most important technologies that enable the concept of B- ISDN, included:

  • Synchronous Digital Hierarchy (SDH ) in Europe, or Synchronous Optical Network ( SONET) in North America
  • ATM: Asynchronous Transfer Mode

The following applications were provided, for example, for the B - ISDN:

  • Moving image communication: video phone, video conferencing, video surveillance
  • Data Communications: LAN connections, CAD / CAM connections, data transmission
  • Message exchange: video e- mail, multimedia documents
  • Demand services: distance learning, databases
  • Message retrieval: video-on -demand, distribution services, radio and television, electronic newspaper

As access network should - be used techniques that use existing telephone and cable networks - next newly laid Direction fiber optic cable. These technologies include the following:

  • High Data Rate Digital Subscriber Line ( HDSL ): Two copper wires are bundled in order / to achieve a transmission capacity of 2 Mbit s in both directions.
  • Asymmetric Digital Subscriber Line (ADSL ): On a local loop can be achieved 1 to 18 Mbit / s in one direction.

For today's broadband networks, the terms B-ISDN or broadband ISDN are no longer used. The main reason for this is that the network design of the B-ISDN proved to be too expensive: IP routers are cheaper than ATM switches. Furthermore, the B-ISDN connection-oriented as compared to the connectionless IP networks would be considerably less suitable for the prevalent today in Internet applications, such as the World Wide Web. The public broadband networks today use while both ATM in the terminal area as well as in the backbone area, but only as transport infrastructure.

Integrated Services Digital Network B channel Videophone Computer-aided manufacturing
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