This paper describes the adaptive component migration facility in the Bifrost Location-Independent Computing System. We present a facility that allows mobile clients to selectively invoke application component functionality locally or remotely in order to improve user response time. The Bifrost runtime system uses a decision-making process that takes into account a variety of issues affecting the migration decision, including client and server resources, component size, the size of the data associated with the component, and network characteristics. We present a detailed design of this system, while examining the options of function call re-direction and API wrappers as a means to extend the semantics of the underlying remote execution technology (DCOM). The adaptivefunctionality provided by Bifrost resulted in a minimum 29% reduction in response time experienced by the client over a default DCOM-based implementation for mobile client devices.
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