A service architecture for ATM: from applications to scheduling

This article derives a rationale for the service architecture of the ATM Forum's Traffic Management 4.0 specification. This model distinguishes a small number of general ways to provide quality of service (QoS) which are appropriate for different classes of applications. We construct the set of ATM service categories by first analyzing the QoS and traffic requirements for a reasonably comprehensive list of applications. The most important application properties and the complexity of the related network mechanisms are used to structure the services. This method has the desirable property that the number of service categories does not expand rapidly with the introduction of new applications. We also discuss packet scheduling as the key component for realizing such a set of services, and report on an experimental realization of a fair queuing scheduler.