Exploiting our computational surroundings for better mobile collaboration

Mobile collaborative environments, being naturally loosely-coupled, call for optimistic replication solutions in order to attain the requirement of decentralized highly available access to data. However, such connectivity as-sumptions are also a decisive hinderance to the ability of optimistic replication protocols to rapidly guarantee con-sistency among the set of loosely-coupled replicas. This paper proposes the extension of conventional opti-mistic replication protocols to exploit the presence of ex-traneous nodes surrounding the group of replica nodes in an increasingly ubiquitous computational universe. In par-ticular, we show that using such extra nodes as temporary carriers of lightweight consistency meta-data may signi-cantly improve the efciency of a replicated system; notably, it reduces commitment delay and conicts, and allows more network-efcient propagation of updates. We support such statement with experimental results obtained from a simu-lated environment.