Reliability analysis of a redundant database for UMTS systems

The Universal Mobile Telecommunication System (UMTS) is anticipated to provide mobile users with new broadband services such as wireless multimedia, including real-time video and high-speed data. In this system, the requirement on service transparency placed by the handling of mobility, both personal and terminal, implies a remarkable increase in the complexity of data management. Therefore, appropriate distributed databases (DDB) must be designed to guarantee speed in the processing and updating of user information, and a high level of reliability and availability. We present a Petri net based model that allows us to analyse a minimally replicated DDB in which different strategies for the replication of user data are adopted. The analysis of the effects of faults in nodes at different levels in the structure is carried out and some scenarios with replicated data are also evaluated.