Optimal Consistent Network Updates in Polynomial Time

  • Pavol Černý
  • Nate Foster
  • Nilesh Jagnik
  • Jedidiah McClurg
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9888)


Software-defined networking (SDN) enables controlling the behavior of a network in software, by managing the forwarding rules installed on switches. However, it can be difficult to ensure that certain properties are preserved during periods of reconfiguration. The widely-accepted notion of per-packet consistency requires every packet to be forwarded using the new configuration or the old configuration, but not a mixture of the two. A (partial) order on switches is a consistent order update if updating the switches in that order guarantees per-packet consistency. A consistent order update is optimal if it allows maximal parallelism, where switches may be updated in parallel if they are incomparable in the order. This paper presents a polynomial-time algorithm for computing optimal consistent order updates. This contrasts with other recent results, which show that for other properties (e.g., loop-freedom and waypoint enforcement), the optimal update problem is np-complete.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Pavol Černý
    • 1
  • Nate Foster
    • 2
  • Nilesh Jagnik
    • 1
  • Jedidiah McClurg
    • 1
  1. 1.University of Colorado BoulderBoulderUSA
  2. 2.Cornell UniversityIthacaUSA

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