QoS agency: an agent-based architecture for supporting quality of service in distributed multimedia systems

The quality of service (QoS) is a core issue in multimedia systems. Intuitively, the QoS states how good the services provided by a multimedia system are. As a rule, the QoS is established through negotiation between users and service providers. The negotiation involves allocation and management of resources in order to attain a desired level of quality. Examples of such resources are peripherals, CPU, network bandwidth, data formats and synchronization levels. The process of negotiation is simple if the resources are managed by a single entity (eg. operating system) or by a set of entities supporting a common negotiation protocol. Unfortunately, in distributed multimedia systems the negotiation and management of resources are far from being simple tasks since resources are diversified, distributed and managed by different entities. In order to minimize such difficulties, an agent-based architecture for QoS negotiation and management is proposed. The architecture combines fixed and mobile agents that interact with the aim of establishing and maintaining a certain level of QoS in a distributed multimedia system. This paper also describes a partial implementation of the proposed architecture using well accepted standards such as CORBA (Object Management Group's Common Object Request Broker Architecture), RTP (Internet's Real Time Protocol), products like Aglets Workbench (a Java based mobile agent framework from IBM) and the Orbix family from Iona.