Localizing link failures in legacy and SDN networks

Localizing network link failures is crucial to guarantee sufficient network capacity and to efficiently manage network resources. However, since most of today's networks use link aggregation to increase bandwidth, localizing a single physical link failure within such aggregated links is challenging. In this paper, we propose and evaluate methods, for both legacy networks as well as SDN networks, to localize link failures in the presence of aggregated links.For legacy networks, we propose STreLo for localizing single link failures. We compare STreLo to a state-of-the-art solution, called SCMon, and show that, at the expense of using more probe packets, it is faster and uses less MPLS labels. Since probe packets are small, we deem the trade-off beneficial.For SDN networks, we propose StaF, which works in a decentralized way, requires no controller interaction, and can adapt to topological changes. Moreover, StaF can localize multi-link failures. Both approaches have been tested via Mininet implementations and experiments.