Transporting compressed video over ATM networks with explicit-rate feedback control

We propose a scheme for transmission of variable bit rate (VBR) compressed video for interactive applications using the explicit-rate congestion-contr ol mechanisms proposed for the available hit rate (ABR) service in asynchro nous transfer mode networks. Compressed video is inherently bursty, with ra te fluctuations over both short and long time scales, This source behavior can be accommodated by the ABR service, since the explicit-rate scheme allo ws sources to request varying amounts of bandwidth over time. Moreover, whe n the bandwidth demand cannot be met, the network provides feedback indicat ing the bandwidth currently available to a connection. In our scheme, the v ideo source rate is matched to the available bandwidth by modifying the qua ntization level used during compression. We use trace-driven simulations to examine how effective the enhanced explicit-rate scheme is in "rate matchi ng" between the network and the source and the effect on end-to-end delay. We also look at the sensitivity of the proposed scheme to the estimates of the network round-trip times and to inaccuracies in the rate requests made by sources.