On defining, computing and guaranteeing quality-of-service in high-speed networks

Future high-speed networks are expected to support a wide variety of services such as voice and video, and to provide a guaranteed quality-of-service (QOS). The authors examine the issues of computing and guaranteeing QOS. Traditionally, the computation of user-oriented performance criteria such as the average delay has been carried out via steady-state analysis of queuing theoretic models of communication networks. It is shown that the steady-state computations are often not sufficient for QOS purposes in future high-speed networks. The authors provide mechanisms for computing and guaranteeing QOS criteria and consider the issue of approximate QOS criteria. It is argued that, for certain envisaged applications, traditional QOS criteria are not appropriate. A QOS criterion for such applications is proposed