A distributed directory scheme in computer networks

In this scheme, each node in the network maintains a local DDB (directory database), and each resource i is registered in the DDBs of all nodes with r/sub i/ hops away from the owning node of resource i, where r/sub i/ denotes the radius of the resource. In general, each resource has a different radius. Whenever a user at a node makes a reference to a resource, the node first searches its local DDB to find an entry for the resource. If this attempt is successful, it is done. Otherwise, the node trigger a query protocol to find the resource. Registered entries are updated for the integrity of stored information every time there are changes in their contents. This scheme uses simple broadcast protocols among the nodes in the network in querying other nodes to find a nonlocal resource and in updating DDBs of other nodes. The authors quantify the response time performance and the overhead associated with the directory scheme as a function of the radius of each resource, and propose an integer programming formulation to determine the optimal radius for each resource which is solved in O(R) steps, where R is the maximum radius of the resource.<>