When trees collide: An approximation algorithm for the generalized Steiner problem on networks

Abstract

We give the first approximation algorithm for the generalized network Steiner problem, a problem in network design. An instance consists of a network with link-costs and, for each pair {i, j} of nodes, an edge-connectivity requirement Tij. The goal is to find a minimum-cost network using the available links and satisfying the requirements. Our algorithm outputs a solution whose cost is within 2 lg R of optimal, where R is the highest requirement value.