Using a Policy Language to Control Tuple-space Synchronization in a Mobile Environment

Any sharing of information using a distributed platform carries the risk of disconnection because of loss of network access. This is particularly the case when considering mobile communication, either using base stations or by forming ad-hoc networks. Replication of shared data is one way to increase data availability in such an environment, but leads to the problem of inconsistency between copies of data, and so requires some means of data synchronization. This paper investigates how policies can be used to resolve data conflict in a way that can be tailored to meet the needs of different types of application in different situations. It discusses a range of application requirements, and describes a policy-based pervasive middleware to support the sharing of data using a tuple-space paradigm. Policies maintained within the middleware are used to trigger a wide range of synchronization options to restore the consistency of the data after periods of disconnected operation.