Mobile agents for QoS tailoring, control and adaptation over the internet: the ubiQoS video on demand service

Service provision over the Internet has to address the issues of differentiated Quality-of-Service (QoS) and ubiquitous accessibility. Internet services should consider user QoS desiderata together with various properties of servers providing replicated/partitioned services and of different access devices/points. The major paper claim is that the provision of services with negotiated and controlled QoS over best-effort networks requires a distributed support infrastructure consisting of active nodes along the path between clients and servers. The paper proposes Mobile Agents (MAs) as a suitable technology to implement active infrastructures and, in particular, presents the MA-based design and implementation of the ubiQoS middleware for Video on Demand. At negotiation time, ubiQoS establishes an active path of intermediate nodes that tailor QoS of multimedia flows depending on user profile and device characteristics. At provision time, ubiQoS controls the offered quality to adapt locally when and where network resource availability changes