Stabilized Branch-and-Price for the Rooted Delay-Constrained Steiner Tree Problem

We consider the rooted delay-constrained Steiner tree problem which arises for example in the design of centralized multicasting networks where quality of service constraints are of concern. We present a mixed integer linear programming formulation based on the concept of feasible paths which has already been considered in the literature for the spanning tree variant. Solving its linear relaxation by column generation has, however, been regarded as computationally not competitive. In this work, we study various possibilities to speed-up the solution of our model by stabilization techniques and embed the column generation procedure in a branch-and-price approach in order to compute proven optimal solutions. Computational results show that the best among the resulting stabilized branch-and-price variants outperforms so-far proposed methods.