Internet Synchronization with Concord

Abstract

Using packet networks to transport multimedia introduces delay v ariations within and across streams, necessitating synchronization at the receiver. This requires stream data to be buffered prior to presentation, which also increases its total end to end delay . Concord recognizes that applications may wish to influence the underlying synchronization policy in terms of its effect on quality of service It provides a single framework for synchronization within and across streams and employs an application specified tradeoff between packet losses, delay and inter-stream skew. This paper presents a new predictive approach for synchronization and a selection of results from an extensive ev aluation of Concord for use in the Internet. A trace driven simulator is used, allowing a direct comparison with alternative approaches. A conclusion is that Concord can operate with lower maximum and v ariation in total end to end delay , which in turn can allow receiver buffer requirements to be reduced.