QoS aware browsing in distributed multimedia systems

Abstract

It has been widely recognized that QoS is important in designing distributed, interactive multimedia systems. However, although much has been said about QoS in the networking domain, and to a lesser degree in processor scheduling, there has hardly been any research activity concerning QoS in the user interface community. We show how the use of 3D graphics techniques in the user interface can lead to a natural way of implicitly specifying and presenting QoS to the end-user. Further, we introduce the concept of generic QoS control tools that allow users to explicitly control and monitor quality of service across different media types. In order to support such a novel user interface, a mechanism is needed to communicate these quality requirements to lower level system components. Although there exists a plethora of QoS architectures that define the semantics and interface of every component in many different ways, none offers a definitive way of structuring QoS aware systems. We instead propose a generalized, abstract concept of QoS for all layers of a software architecture. Each layer in a software system deals with QoS at its appropriate level of abstraction using a generic API for communicating QoS parameters and values to layers above and below. We call the aggregation of these parameters and values a “service contract”. This abstract concept can be applied recursively to build hierarchies of services. This paper describes our framework for building QoS aware software systems and explains in detail the user interface for a multimedia browser as an example application.