A practical methodology for guaranteeing quality of service for video-on-demand

A novel and simple approach for defining end-to-end quality of service (QoS ) in video-on-demand (VoD) services is presented. Using this approach, we d erive a schedulable region for a video server which guarantees end-to-end Q oS, where a specific QoS required in the video client translates into a QoS specification For the video server. Our methodology is based on a generic model for VoD services, which is extendible to any VoD system. In this kind of system, both the network and the video server are potential sources of QoS degradation. Specifically, we examine the effect that impairments in th e video server and video client have on the video quality perceived by the end user. The Columbia VoD testbed is presented as an example to validate t he model through experimental results. Our model can he connected to networ k QoS admission-control models to create a unified approach for admission c ontrol of incoming video requests in the video server and network.