Data transfer evaluation of nomadic data consistency model for large-scalemobile systems

The optimistic consistency scheme has been established with respect to data consistency and availability in distributed systems. The nomadic data cons istency model using version vectors to support data versioning for data syn chronization and concurrent conflict detection is suitable for an optimisti c replication system that supports large-scale wireless networks. This pape r describes the architecture and its data consistency model using data vers ioning and its access domain control targeted for nomadic data sharing syst ems, such as collaborative works using database and messaging, and the data transfer optimizations of the model. We evaluate our data versioning schem e comparing: with a traditional data versioning and the data transfer optim ization by estimation and measurement assuming a mobile worker's job. We ge nerate arithmetic formulas for data transfer estimation using the optimizin g techniques and apply them to large-scale data sharing configurations in w hich collaboration groups are dynamically formed and data is exchanged in e ach group. The data versioning with an access domain increases flexibility in data sharing configurations, such as mobile collaboration systems and cl ient/server type mobile systems. We confirmed that the combination of the g eneral optimizations and the access domain configurations based on our data consistency model is applicable for large-scale mobile data sharing system s.