Quality of service management and control of multimedia applications: a scenario and two simple strategies

Management and control of multimedia traffic is considered within a scenario characterized by the presence of different network platforms, exhibiting possibly very different features in terms of quality of service (QoS). In this framework, the needs for control strategies, acting in the user plane at protocol layers above the transport is examined and their goals, possible actions, information bases and location (centralized/decentralized) are discussed. Two specific strategies for QoS control of a multimedia connection involving real time traffic (voice and video) are then introduced; one is based on a backoff procedure at the transmitter, while the other acts upon feedback from the receiver to change some features of the coding algorithm. The joint operation of both control strategies is examined in an experimental environment based on Ethernet networks, interconnected by IP routers.