Communication of multimedia data among multiple parties can be costly
in terms of the use of network resources if guaranteed quality of serv
ice is requested. We believe, however, that knowledge of the functiona
l characteristics of real applications can be helpful in devising new
mechanisms to support isochronous communication efficiently. In this p
aper, we follow this approach to introduce a new communication abstrac
tion, called the half-duplex real-time channel. The new abstraction ca
n reduce the resources needed by real-time protocols to offer gurantee
d performance networking by exploiting the interaction patterns typica
l of multimedia applications such as teleconferencing and teleeducatio
n.