Conngured Replication for Mobile Applications

Replication is an essential utility in mobile environments. Mobile units not connected to xed networks are left with their own data resources which may or may not contain the necessary data. This paper describes beneets and problems using replication in mobile infrastructures. We compare diierent replication approaches for xed and mobile systems. We show that traditional protocols are inadequate for the requirements of mobile environments, especially by accessing multimedia data. The objectives of replication, high availability, permanent consistency and low communication costs, are incompatible. Consequently, replication protocols must nd suitable compromises. However, rather than creating a general approach for all possible mobile environments, we tailor suitable replication mechanisms for special mobile environments and data types. This approach allows for conngured replication based on various environmental and data characteristics.