Adaptive group communication services for groupware systems

Collaborative, multi-user applications require group multicast services that provide ordering guarantees for maintaining consistency of replicated shared context as well as providing a high degree of interactivity, even under varying load on the communication servers. While the most common view of the quality of service (QoS) in a distributed system is in terms of the guarantee of the network connection parameters (bandwidth, end-to-end delay) for audio and video, in this paper we investigate the various requirements placed on group communication servers for reliable data communication among diverse groups of collaborative users. We show that in the absence of such considerations in the design of a group communication service, some groups or individual users can be severely affected by bursty traffic or increases in the size of other groups. We present the design of a best-effort adaptive group communication service for supporting reliable data communication in CSCW systems, which addresses both group´s requirements and individual user´s requirements, balancing the needs of multiple groups of users by taking into account their priorities and needs when resources are constrained at the communication server