Delay-constrained unicast and the triangle-cast problem

Chandra Chekuri, Sudeep Kamath, Sreeram Kannan, Pramod Viswanath

Research output: Chapter in Book/Report/Conference proceedingConference contribution

15 Scopus citations


We consider the single-unicast communication problem in a network with a delay constraint. For this setting, it has recently been shown that network coding offers an advantage over routing. We show that the existing upper bound in the literature on the capacity offered by network coding can be a factor of Θ(D) larger than the true capacity where D is the delay bound. In this work, we tighten this gap significantly to 8 log(D + 1) by proving a new upper bound. The key insight is a connection to a new traffic model that we call triangle-cast (or degraded multiple-unicast), for which we obtain a logarithmic flow-cut gap by suitably adapting the techniques from the approximation algorithms literature.

Original languageEnglish (US)
Title of host publicationProceedings - 2015 IEEE International Symposium on Information Theory, ISIT 2015
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages5
ISBN (Electronic)9781467377041
StatePublished - Sep 28 2015
Externally publishedYes
EventIEEE International Symposium on Information Theory, ISIT 2015 - Hong Kong, Hong Kong
Duration: Jun 14 2015Jun 19 2015

Publication series

NameIEEE International Symposium on Information Theory - Proceedings
ISSN (Print)2157-8095


OtherIEEE International Symposium on Information Theory, ISIT 2015
Country/TerritoryHong Kong
CityHong Kong

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • Information Systems
  • Modeling and Simulation
  • Applied Mathematics


  • delay-constrained unicast
  • generalized network sharing bound
  • region-growing lemma
  • triangle-cast


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