Middleware provides distributed objects with a software infrastructure that offers a set of well-known distribution transparencies. These transparencies enable the rapid introduction of applications for heterogeneous, distributed systems. However, to support guaranteed Quality of Service (QoS) system-specific QoS mechanisms need to be controlled. Accessing the low-level mechanisms directly by applications crosscuts the transparency offered by the middleware and limits portability and interoperability. The challenge for next-generation middleware is to support application-level QoS requirements, while maintaining the advantages of the distribution transparencies. This paper presents three contributions: (1) An architecture for a QoS-aware software infrastructure for distributed objects (2) A framework for a QoS provisioning service (QPS) and (3) An evaluation of the QPS framework by means of a prototype that supports performance

Abstract