Towards an efficient ATM best effort video delivery service

This paper addresses the transport of real-time multimedia traffic generated by MPEG-2 applications over ATM networks using an enhanced UBR best effort service (UBR+). Based on the factors affecting the picture quality during transmission, we propose an efficient and cost-effective ATM best effort delivery service. The proposed service integrates three components: a dynamic frame level priority assignation mechanism based on the MPEG data structure and feedback from the network (DexPAS), a novel audiovisual AAL5 SSCS with FEC, and an intelligent packet video discard scheme named SA-PSD, which adaptively and selectively adjusts the cell drop level to switch buffer occupancy, video cell payload type and forward error correction ability of the destination. The overall best effort video delivery framework is evaluated using ATM network simulation and MPEG-2 video traces. The ultimate aim of this framework is twofold. First, minimizing loss for critical video data with bounded end-to-end delay for arriving cells. Second, reducing the bad throughput crossing the network during congestion. Compared to previous approaches, performance evaluation shows a good protection of predictive coded and bidirectional predictive coded frames at the video slice layer.