A Benders Decomposition Approach for Static Data Segment Location to Servers Connected by a Tree Backbone

Abstract

We consider the problem of allocating database segments to the locations of a content distribution network (CDN). Many other decisions such as server location, query routing, user assignment and network topology are also addressed simultaneously. We consider the problem with the backbone (server network) being restricted to be a tree. Although it is an extremely hard problem to solve in its original form, prior information on the segment allocation, server location, and the tree backbone, reduces the original problem to a simple assignment problem, and therefore, indicates the suitability of a decomposition approach. We formulate the problem and develop a Benders decomposition approach. Due to the hardness of the master problem, we solve it heuristically to obtain a reasonable upper bound on the original problem in a short period of time. The success of the algorithm is particularly significant in large problems, for which CPLEX struggles to obtain even a feasible integer solution.