Dynamic QoS Management for Scalable Video Flows

We introduce the concept of Dynamic QoS Management (DQM) for control and management of hierarchically coded flows operating in heterogeneous multimedia networking environments. The motivation that underpins our scheme is to bridge the heterogenity gap that exists between applications, end-systems and networks. Q o S adaptors, QoS filters and QoS groups are key scalable objects used in resolving quality of service capability mismatch. QoS filters manipulate hierarchically coded flows as they progress through the communications system, QoS adaptors scale flows at the endsystems based on the flow's measured performance and user supplied QoS scaling policy, and QoS groups provide baseline quality of service for multicast communications. The focus of the work is driven by a) the special features of scalable video flows in particular MPEG2, b) the needs of both scalable and single-layer video for transmission over multimedia networks such as ATM. A novel adaptive network service is proposed for the transmission of multi-layer coded flows that offers "hard" guarantees to the base layer, and "fairness" guarantees to the enhancement layers based on a new bandwidth allocation technique called Weighted Fair Sharing (WFS).