A Case for Proactivity in Directory Services

Innovative and widely distributed applications are enabled by infrastructure layers that allow distributed resources and services to be pooled and managed as though they were locally available. Advances in communication technologies and the proliferation of computing devices have made this possible; two such types of infrastructures are pervasive computing environments and computational grids. An important component of both types of infrastructures is a directory service that provides information about different objects in the environment, such as resources and people, to applications and their users. Well-known examples of such services are the Metacomputing Directory Service for Globus-based environments, and the Intentional Naming System (INS) for applications developed in the Oxygen pervasive computing project. Directory services in both types of environments must support sophisticated object descriptions and query patterns, operate in highly dynamic environments, and scale to an increasingly large number of objects and users.