Multimedia networks and the public switched telephone network

The coherence of the public switched telephone network (PSTN) was based on the understanding that, to further common interests, the terminals and networks were to be coordinated to allow the transparent flow of traffic. Innovations were evaluated based on the overall system performance and the potential number of connections. The evolution of public networks and technological advancements, of course, have allowed traffic types other than speech to be carried over the PSTN. However, because stakeholders in multimedia communications often have conflicting requirements, they usually promote application-specific approaches to code source information and multiplex the different media streams. Rarely do they ponder over possible ways to merge all these approaches in a harmonious way. Multimedia communications straddle the traditions of both telecommunications and information technologies. As the technology evolves, it is becoming increasingly difficult to identify the boundary of "networks".