Many of the visions of new usages of telecommunications have been bound to the concept of multimedia, a maybe overloaded word which at a user level seems to denote a desire to utilize richer ways of interacting with terminals. Examples include teleconferencing, distance work, distance education, distance consultancy, distant information access, etc. That is, most of what we do today, but independent of physical proximity. Many technical challenges remain, and one is the design of the global network platform that is to enable those services. We discuss what is special to multimedia communications, derive a number of requirements based on a model of typical services and applications, and propose a new higher level of support to enable the efficient production of such systems.