Abstract

We introduce a new class of problems called network information flow which is inspired by computer network applications. Consider a point-to-point communication network on which a number of information sources are to be multicast to certain sets of destinations. We assume that the information sources are mutually independent. The problem is to characterize the admissible coding rate region. This model subsumes all previously studied models along the same line. We study the problem with one information source, and we have obtained a simple characterization of the admissible coding rate region. Our result can be regarded as the max-flow min-cut theorem for network information flow. Contrary to one's intuition, our work reveals that it is in general not optimal to regard the information to be multicast as a "fluid" which can simply be routed or replicated. Rather, by employing coding at the nodes, which we refer to as network coding, bandwidth can in general be saved. This finding may have significant impact on future design of switching systems.

Keywords

MulticastLinear network codingComputer scienceTheoretical computer scienceCoding (social sciences)IntuitionInformation flowFlow networkPoint-to-pointComputer networkMathematical optimizationMathematicsNetwork packet

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Publication Info

Year
2000
Type
article
Volume
46
Issue
4
Pages
1204-1216
Citations
7777
Access
Closed

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Cite This

Rudolf Ahlswede, Ning Cai, Shuo Li et al. (2000). Network information flow. IEEE Transactions on Information Theory , 46 (4) , 1204-1216. https://doi.org/10.1109/18.850663

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DOI
10.1109/18.850663