This paper considers the support of real-time applications in an Integrated Services Packet Network (ISPN). We rst review the characteristics of real-time applications. We observe that, contrary to the popular view that real-time applications necessarily require a xed delay bound, some realtime applications are more
exible and can adapt to current network conditions. We then propose an ISPN architecture that supports two distinct kinds of real-time service: guaranteed service, which is the traditional form of realtime service discussed in most of the literature and involves pre-computed worst-case delay bounds, and predictedservice which uses the measured performance of the network in computing delay bounds. We then propose a packet scheduling mechanism that can support both of these real-time services as well as accommodate datagram trac. We also discuss two other aspects of an overall ISPN architecture: the service interface and the admission control criteria.
David D. Clark, Scott Shenker, Lixia Zhang