On the Integrality Gap of a Natural Formulation of the Single-sink Buy-at-Bulk Network Design Problem

  • Naveen Garg
  • Rohit Khandekar
  • Goran Konjevod
  • R. Ravi
  • F. S. Salman
  • Amitabh Sinha
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2081)


We study two versions of the single sink buy-at-bulk network design problem. We are given a network and a single sink, and several sources which demand a certain amount of flow to be routed to the sink. We are also given a finite set of cable types which have different cost characteristics and obey the principle of economies of scale. We wish to construct a minimum cost network to support the demands, using our given cable types. We study a natural integer program formulation of the problem, and show that its integrality gap is O(k), where k is the number of cable types. As a consequence, we also provide an O(k)-approximation algorithm.


Short Path Approximation Algorithm Steiner Tree Network Design Problem Integer Program Formulation 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Naveen Garg
    • 1
  • Rohit Khandekar
    • 1
  • Goran Konjevod
    • 2
  • R. Ravi
    • 3
  • F. S. Salman
    • 4
  • Amitabh Sinha
    • 3
  1. 1.Department of Computer Science and EngineeringIndian Institute of TechnologyNew DelhiIndia
  2. 2.Department of Computer Science and EngineeringArizona State UniversityUSA
  3. 3.GSIACarnegie Mellon UniversityPittsburghUSA
  4. 4.Krannert School of ManagementPurdue UniversityUSA

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