H.-C. Lin and S.L. Lee (Taiwan)
: Causal ordering, distributed systems, group
communication, region-tree, member-group, multicast.
This paper examines what kind of architecture is suited to
virtual communities and how to maintain the “cause and
effect relationship” between messages for supporting real
time interactive communication in virtual communities. In
view of the difﬁculties arising from virtual communities,
we propose the Member-Group Agent (MGA) architecture
where each MGA functions as a serving agent for the cor
responding communication of Member-Group (MG) mem
bers with common membership. In our message ordering
scheme, each message sent from MGA is piggybacked on
an immediate causal set, which identiﬁes the immediate,
causally prior messages upon which the message is based.
The simulation results show that the immediate causal set
scheme can cooperate with the proposed region-tree archi
tectures well, and the proposed methods are adaptive to the
scalability of the system.