On the Price of Locality in Static Fast Rerouting

Klaus-Tycho Foerster (1) , Juho Hirvonen (2) , Yvonne-Anne Pignolet (3) , Stefan Schmid (4, 1) , Gilles Tredan (5)

1 TU - Technische Universität Dortmund [Dortmund]
2 Aalto University
3 DFINITY Foundation [Zurich]
4 University of Vienna [Vienna]
5 LAAS-TSF - Équipe Tolérance aux fautes et Sûreté de Fonctionnement informatique

Modern communication networks feature fully decentralized flow rerouting mechanisms which allow them to quickly react to link failures. This paper revisits the fundamental algorithmic problem underlying such local fast rerouting mechanisms. Is it possible to achieve perfect resilience, i.e., to define local routing tables which preserve connectivity as long as the underlying network is still connected? Feigenbaum et al. [1] and Foerster et al. [2] showed that, unfortunately, it is impossible in general. This paper charts a more complete landscape of the feasibility of perfect resilience. We first show a perhaps surprisingly large price of locality in static fast rerouting mechanisms: even when source and destination remain connected by a linear number of link-disjoint paths after link failures, local rerouting algorithms cannot find any of them which leads to a disconnection on the routing level. This motivates us to study resilience in graphs which exclude certain dense minors, such as cliques or a complete bipartite graphs, and in particular, provide characterizations of the possibility of perfect resilience in different routing models. We provide further insights into the price of locality by showing impossibility results for few failures and investigate perfect resilience on Topology Zoo networks.

Domaines: Informatique [cs]

Klaus-Tycho Foerster, Juho Hirvonen, Yvonne-Anne Pignolet, Stefan Schmid, Gilles Tredan. On the Price of Locality in Static Fast Rerouting. 52nd Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN), Jun 2022, Baltimore, United States. pp.215-226, ⟨10.1109/dsn53405.2022.00032⟩. ⟨hal-03859648⟩