Distributed QoS Management for A Multiparty Video Conferencing System

The QoS management for distributed interactive multimedia applications is currently mostly based on centralized approaches in which a single group server manages the QoS requirements for all participants. Group servers are simplier to handle, but they may become a weak point of the system due to server failures or performance bottlenecks. In order to avoid these problems and to better support the application in the endsystems a distributed QoS management at the application level seems to be more appropriate. In the paper we present such a distributed QoS management. It has been designed and implemented for the multiparty video conferencing system GCSVA. The basic idea of our approach consists in a decentralized calculation and assignment of the bandwidth quota for the speaker and listener whereby the receiving capacity of the most powerful participant is taken as measure. Less powerful receivers scale down the data rate of the incoming video streams by filtering according to their performance parameters. The consistency of the QoS data in the endsystems is ensured by means of a specialized group communication protocol which provides a reliable, atomic and ordered delivery service. 1 In: Yongchareon, T.; Aagesen, F. A.; Wuwongse, V. (eds.): Intelligence in Networks. IFIP TC6 WG6.7 5th International Conference, SMARTNET’99, Pathumthani, Thailand, Kluwer Academic Publishers, 1999, 335 348. 2 Ines Beier, Hartmut Koenig