File Allocation in a Distributed Computer Communication Network

An algorithm is presented to determine locations for the storage of copies of files in store-and-forward computer communications networks. The algorithm determines storage locations which minimize the sum of network file storage costs and message transmission costs. Networks that use adaptive routing techniques are the primary focus. Feasible file locations must satisfy network performance requirements for file availability and delay by message class. An effective method of evaluating delay constraints for networks using adaptive routing techniques is introduced. The algorithm uses the solution to a p-median problem to identify initial candidate file placements. Interaction between a set of file movement rules and a network simulator is employed to modify initial placements to fmd near-optimal locations which satisfy the network performance constraints.