Traffic analysis for multiparty videoconferencing in virtual path-based ATM networks

With e!ective bandwidth concept encapsulating cell-level behaviour, asynchronous transfer mode (ATM) network design and analysis at the call-level may be formulated in the framework of circuit-switched loss networks. In this paper, we develop an analytical framework for a kind of multiparty videoconferencing in the VP-based ATM network at call-level. For this kind of conference, only the video of the current speaker is broadcast to other conferees. We "rst address several conference management issues in the VP-based ATM network, including the bandwidth allocation strategies, routing rule, call admission policy and speaker change management. Next, we formulate a tra$c model for the conferences. Since an exact analysis of such a multiparty conference network is mathematically intractable, an approximate analysis for such conferences in a fully connected VP network is performed. The key of our method is to make use of the reduced-load approximation and open Jackson network model to derive the tra$c loads from new conferences as well as that from the speaker change of the on-going conferences. Our study shows that the proposed analysis can give accurate predictions of the blocking probabilities for the new conference calls as well as video freeze probabilities for the on-going conferences. Copyright ( 2000 John Wiley & Sons, Ltd.