Departmental Papers (CIS)

Date of this Version


Document Type

Journal Article


Copyright SIAM 2009. Reprinted from:
A Constant Factor Approximation for the Single Sink Edge Installation Problem Sudipto Guha, Adam Meyerson, and Kamesh Munagala, SIAM J. Comput. 38, 2426 (2009), DOI:10.1137/050643635


We present the first constant approximation to the single sink buy-at-bulk network design problem, where we have to design a network by buying pipes of different costs and capacities per unit length to route demands at a set of sources to a single sink. The distances in the underlying network form a metric. This result improves the previous bound of O(log |R|), where R is the set of sources. We also present a better constant approximation to the related Access Network Design problem. Our algorithms are randomized and combinatorial. As a subroutine in our algorithm, we use an interesting variant of facility location with lower bounds on the amount of demand an open facility needs to serve. We call this variant load balanced facility location and present a constant factor approximation for it, while relaxing the lower bounds by a constant factor.


approximation algorithms, network design, Steiner trees, facility location



Date Posted: 08 June 2009

This document has been peer reviewed.