Network Support for Multicast Video Distribution

Multicast video distribution in a best-eeort environment presents challenges to system designers, including heterogeneity in the bandwidth availability on the paths from the sender to the receivers and dynamic behavior in the network and set of receivers over time. Classic approaches to dealing with dynamic conditions involve adaptation at the sender (for unicast) and adaptation driven by the receivers (for multi-cast). Both approaches have limitations that aaect the quality of video received. In this paper, we consider a third option for the location of adaptation, namely: in the network. Since the adaptation is applied inside the network, the time and place for adaptation can better match network conditions. Further , the adaptation can occur more rapidly, without the need for route changes. Finally, the adaptation can occur at ner granularity, providing better quality and more graceful degradation to receivers. The point of this paper is to quantify the potential bene-ts of in-network adaptation for multicast video distribution .