Admission Control for Multimedia Delivery Over Deadline-Based Networks

Increasing demand to transmit real-time data over packet-switched networks calls for quality-of-service support from the underlying network. Deadline-based networks were developed for this purpose. In a deadline-based network, each application data unit (ADU) is associated with a delivery deadline, it is specified by the sending application and represents the time at which the ADU should be delivered at the receiver. The ADU deadline is mapped to packet deadlines, which are carried by packets and used by routers for channel scheduling; deadline- based scheduling is employed in routers. It was shown that a deadline-based network provides better support to real-time data delivery than a first-come-first-served network. We study how to effectively and efficiently deliver multimedia data in deadline- based networks, especially when at heavy load. When network load is high, congestion may occur. Multimedia data may miss their delivery deadlines due to excessive queueing delays and high packet loss ratios. This would directly affect the playback quality at the application layer. To control the level of load and improve performance, two end-system based admission control algorithms are developed. Their performance is evaluated using simulation. Both schemes are shown to improve the performance of multimedia delivery over deadline-based networks.