Some of the fixed hosts, called base stations, are augmented with a wireless interface to communicate with mobile hosts. The geographical area covered by a base station is called a cell. These databases, for reasons of reliability, performance, and cost will be distributed and replicated over many sites. The use of replicated databases entails both a schema for placing and locating copies, and concurrency and replica control protocols for ensuring correctness. Challenges in Data Management .
Mobile computing is susceptible to frequent network disconnections.
Mobile clients deliberately avoid use of the wireless links to reduce cost and power consumption and to overcome availability and latency barriers. Mobile users will desire access to private or corporate databases that will be stored at mobile as well as static hosts and queried and updated over the wired and the wireless network. Challenges in Data Management . 5 describes how we achieve easy access to multiple databases with the database interface. Section 6 provides our experience in prototype implementation and evaluation.