Traffic engineering with Equal-Cost-Multipath: An algorithmic perspective

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

44 Scopus citations


To efficiently exploit network resources operators do traffic engineering (TE), i.e., adapt the routing of traffic to the prevailing demands. TE in large IP networks typically relies on configuring static link weights and splitting traffic between the resulting shortest-paths via the Equal-Cost-MultiPath (ECMP) mechanism. Yet, despite its vast popularity, crucial operational aspects of TE via ECMP are still little-understood from an algorithmic viewpoint. We embark upon a systematic algorithmic study of TE with ECMP. We consider the standard model of TE with ECMP and prove that, in general, even approximating the optimal link-weight configuration for ECMP within any constant ratio is an intractable feat, settling a long-standing open question. We establish, in contrast, that ECMP can provably achieve optimal traffic flow for the important category of Clos datacenter networks. We last consider a well-documented shortcoming of ECMP: suboptimal routing of large ('elephant') flows. We present algorithms for scheduling 'elephant' flows on top of ECMP (as in, e.g., Hedera [1]) with provable approximation guarantees. Our results complement and shed new light on past experimental and empirical studies of the performance of TE with ECMP.

Original languageAmerican English
Title of host publicationIEEE INFOCOM 2014 - IEEE Conference on Computer Communications
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages9
ISBN (Print)9781479933600
StatePublished - 2014
Event33rd IEEE Conference on Computer Communications, IEEE INFOCOM 2014 - Toronto, ON, Canada
Duration: 27 Apr 20142 May 2014

Publication series

NameProceedings - IEEE INFOCOM
ISSN (Print)0743-166X


Conference33rd IEEE Conference on Computer Communications, IEEE INFOCOM 2014
CityToronto, ON


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