A control service for QoS-enabled middleware

Abstract. Developers of distributed multimedia applications face a diversity of multimedia formats, streaming platforms and streaming protocols; furthermore, support for end-to-end Quality-of-Service (QoS) is a crucial factor for the development of future distributed multimedia systems. Middleware is gaining wide acceptance as a generic software infrastructure for distributed applications, a growing number of applications are designed and implemented as a set of collaborating objects using object middleware, such as CORBA, EJB and (D)COM(+), as a software infrastructure that facilitates distribution transparent interactions. However, quality aspects of interactions between objects cannot be specified nor enforced by current object middleware, resulting only in a best-effort QoS support in middleware. Next generation object middleware should offer abstractions for management and control of the system level QoS mechanisms, while maintaining the advantages of the distribution transparencies, these abstractions should take into account that new interfaces to OS resources and new network protocols are expected to appear as the result of ongoing research efforts, in addition, a changing run-time environment must be handled. The paper discusses the design and implementation of a QoS-enabled middleware platform for content delivery with QoS guarantees. Properties of content are represented using a generic content representation model described using the OMG Meta Object Facility (MOF) model. The integration of the QoS support, content representation and content delivery framework results in a QoS-enabled middleware which is representation, location and QoS transparent. This paper presents aspects of the framework for controlling QoS at middleware level implemented as a provisioning QoS service, suport ing new paradigm QoS-enabled middleware. Key words: QoS control, a service for QoS- enabled middleware, adaptive middlewar