Active middleware for Internet Video on Demand: the QoS-aware routing solution in ubiQoS
Several factors are forcing to address the issues of differentiated Quality of Service (QoS) and ubiquitous accessibility in Internet services, from growing user requirements to the increasing heterogeneity of access devices, from the competition of service providers to the severe constraints of resource availability in emerging wireless environments. The paper claims that the provision of services with negotiated and controlled QoS over best-effort networks is achievable via distributed support infrastructures that activate some of the nodes along the network path between clients and servers. The paper proposes mobile agents (MAs) as the activation technology to implement the needed active infrastructure and the MA-based design and implementation of the ubiQoS middleware for Video on Demand. At the starting of the service session, ubiQoS establishes an active path of intermediate nodes capable of tailoring multimedia flow QoS depending on profiles of user preferences and of device characteristics; at provision time, ubiQoS monitors the offered quality and promptly react to changes in resource availability by locally performing multimedia transcoding/downscaling and resource pre-emption. In particular, the paper focuses on how it is possible to determine dynamically a QoS-aware active path between clients and servers, discusses alternative solutions, and evaluates the performance results of the completely decentralized Peer-to-Peer implementation of the active path determination in ubiQoS.
middleware video on demand quality of service mobile agents active services