To answer the question above, the following terms need to be defined:
� Telecommunications (telecom) refers to communications over a distance;
communications within a single facility are usually not included
under the telecom umbrella;
� Telecom convergence includes transport convergence
and the convergence of telecom services;
� Transport convergence means that different types of data are
transported through a common network in a similar manner;
� Convergence of telecom services implies that different applications are
handled in a similar manner from the point of view of the user, with a
common user-to-network interface (UNI) for different applications;
� Data communications (datacom) usually refers to communications
between computers or between a computer and a peripheral device; with the
advent of convergence, datacom and telecom are no longer distinct terms.
Transport Convergence
For the most part, voice has been transported via circuit switching and computer data has been transported via packet switching. Data networks, such as the networks that constitute the Internet, have been overlaid on the telephone networks.
With transport convergence, various types of data can be handed in the same way and transported through a common integrated network. One way to achieve transport convergence is to packetize all data as it enters the network and switch the packets using common networks elements. For example, all data could be converted to Asynchronous Transfer Mode (ATM) cells and switched by ATM switches.
Transport convergence is not necessarily visible to the user. User interfaces may be different for different services that employ the same transport mechanism. For example, Frame Relay service may employ ATM transport with frames broken up into ATM cells to be transported through the network. Even though they employ a common transport mechanism, Frame Relay and ATM services would employ different user interfaces.
Convergence of Services
With the convergence of services, different applications would be handled in same way from a customer (user) perspective. For example, an IP router at the customer premise could handle both computer data and voice over IP. Converged services require broadband access, particularly for video.
Ideally, fiber access via fiber-to-the-premise (FTTP) would be provided for all subscribers. However, deploying FTTP involves a very large capital expense, and it will take a long time before FTTP is available everywhere. In the meantime it is feasible to support converged services using digital subscriber line (DSL) techniques.
With converged services, different types of data could be transported differently by the network. For example, time sensitive data, such as voice, could be given priority. However, it would still make sense to use a common transport network and common network elements even if different transport methods are employed.
Triple Play
Providing voice, video, and data communications over a common network with a common user interface is often referred to as "the triple play." A paper describing how the triple play can be supported over existing telephone lines was published by the International Engineering Consortium in their comprehensive report entitled Achieving the Triple Play: Technology and Business Models for Success (copyright 2006).