Abstract
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 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(log δ)-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.
Original language | English |
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Pages (from-to) | 1903-1921 |
Number of pages | 19 |
Journal | SIAM Journal on Discrete Mathematics |
Volume | 32 |
Issue number | 3 |
DOIs | |
State | Published - 2018 |
Bibliographical note
Publisher Copyright:© 2018 Society for Industrial and Applied Mathematics.
Funding
∗Received by the editors November 10, 2016; accepted for publication (in revised form) May 14, 2018; published electronically August 1, 2018. A preliminary version was presented at the 39th International Colloquium on Automata, Languages and Programming (ICALP), Springer, Heidelberg, 2012. http://www.siam.org/journals/sidma/32-3/M110301.html Funding: This work was supported in part by the Networking HDTV from the Open Internet (Net-HD) Consortium, Israel. The second author’s work was supported by Eshkol fellowship, the Ministry of Science and Technology, Israel. The third author’s work was supported in part by the Israel Science Foundation and by the Technion Gordon Center. The fourth author’s work was supported in part by the Israel Science Foundation (grant 497/14). †Department of Computer Science, Technion, Haifa 32000, Israel ([email protected]). ‡Technion, Haifa 32000, Israel ([email protected]). §Information Systems Group, Faculty of IE&M, Technion, Haifa 32000, Israel ([email protected]). ¶Faculty of Engineering, Bar-Ilan University, Ramat Gan 52900, Israel ([email protected]).
Funders | Funder number |
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Technion Gordon Center | |
Israel Science Foundation | 497/14 |
Ministry of science and technology, Israel |
Keywords
- Approximation algorithm
- Content delivery network
- Online Steiner tree
- Online algorithm