Communications costs under alternative distributed database configurations

Distributed database management systems (DDBMSs) can be configured in a variety of ways. Full or partial replication of data may be utilized, and even within systems not allowing replication a variety of directory configurations might be used, including fully replicated, centrally replicated and distributed directory systems. Alternative DDBMS configurations may lead to very different communications costs in a distributed network, and changes in database usage patterns are likely to affect different configurations in different ways. This paper models the communications costs associated with several alternative DDBMS configurations and examines the impact of changing database usage patterns on those costs. Changes in usage are found to have a substantial impact on relative communications costs of the alternative configurations.