| description |
Data consistency protocols are vital ingredients of mobile data
management systems. Notable research efforts have been spent to find
adequate consistency models for allowing mobile and nomadic users to
share mutable data. Recently, mobile Ambient Service infrastructures
that pose somewhat different requirements have entered the focus of
attention. Such services are not as loosely coupled as the
afore-mentioned systems, but they still need flexible consistency
protocols that may adapt to the current dynamics in the system. We
propose an extension to the well-known anti-entropy protocol that
makes use of the nature of Ambient Service environments to allow for
a flexible consistency management among arbitrary groups of mobile
service replicas. We will show that our protocol can exploit the
concept of group updates to increase its efficiency in terms of
bandwidth usage. Furthermore, we prove that it avoids costly state
transfers by means of a simple rule that limits the divergence
within the overall set of replicas. Finally, we introduce two simple
tunable parameters, and we present experimental results that show
how they may be used to shape the characteristics of the protocol.
|