The Power of Two in Consistent Network Updates: Hard Loop Freedom, Easy Flow Migration

The Power of Two in Consistent Network Updates: Hard Loop Freedom, Easy Flow Migration

Abstract

We study complexity and algorithms for network updates in the setting of Software Defined Networks. Our focus lies on consistent updates for the case of updating forwarding rules in a loop free manner and the migration of flows without congestion. In both cases, we study how the power of two affects the respective problem setting. For loop freedom, we show that scheduling consistent updates for two destinations is NP-hard for a sublinear number of rounds. We also consider the dynamic case, and show that this problem is NP-hard as well via a reduction from Feedback Arc Set. While the power of two increases the complexity for loop freedom, the converse is true when allowing to split flows twice. For the NP-hard problem of consistently migrating unsplittable flows to new routes while respecting waypointing and service chains, we prove that two-splittability allows the problem to be tractable again.

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Authors
  • Foerster, Klaus-Tycho
  • Wattenhofer, Roger
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Supplemental Material
Shortfacts
Category
Paper in Conference Proceedings or in Workshop Proceedings (Paper)
Event Title
25th International Conference on Computer Communication and Networks (ICCCN 2016)
Divisions
Communication Technologies
Subjects
Rechnerperipherie, Datenkommunikationshardware
Event Location
Waikoloa, USA
Event Type
Conference
Event Dates
1-4 Aug 2016
Date
August 2016
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