Multimedia bridging: a structured view

Abstract

Multimedia, multipoint applications require the processing and coordination of audio, video and data, to unsure that each participant or user receives the proper media traffic mix in the expected format at the expected time. Such a requirement is met by multimedia bridging, which encompasses many functions, including, event ordering, multimedia synchronization, network-user interfacing, media processing and distribution. In practice, bridging functions are either implicitly embedded in the software of distributed multipoint applications or they are centrally located on a hardware component embedded in the network, called a "bridge", usually designed to support a single multipoint application, such as teleconferencing. This paper presents a structured view of the multimedia bridging problem. Our premise is that a bridge should be viewed as a logical entity which provides a set off functions that are transparently accessible to many multipoint applications. Whether bridging functions are physically resident at an end-point or in a network, and whether they are implemented in software or in hardware is a matter of performance, efficiency and cost trade-offs which remain to be evaluated. We believe that this is a first step towards developing more flexible bridging infrastructures.