Growing Half-Balls: Minimizing Storage and Communication Costs in CDNs

  • Reuven Bar-Yehuda
  • Erez Kantor
  • Shay Kutten
  • Dror Rawitz
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7392)


The Dynamic Content Distribution problem addresses the trade-off between storage and delivery costs in modern virtual Content Delivery Networks (CDNs). That is, a video file can be stored in multiple places so that the request of each user is served from a location that is near by to the user. This minimizes the delivery costs, but is associated with a storage cost. This problem is NP-hard even in grid networks. In this paper, we present a constant factor approximation algorithm for grid networks. We also present an O(logδ)-competitive algorithm, where δ is the normalized diameter of the network, for general networks with general metrics. We show a matching lower bound by using a reduction from online undirected Steiner tree. Our algorithms use a rather intuitive approach that has an elegant representation in geometric terms.


Communication Cost Steiner Tree Competitive Ratio Steiner Tree Problem Horizontal Edge 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Reuven Bar-Yehuda
    • 1
  • Erez Kantor
    • 1
  • Shay Kutten
    • 1
  • Dror Rawitz
    • 2
  1. 1.TechnionHaifaIsrael
  2. 2.Tel-Aviv UniversityTel-AvivIsrael

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