Fault localization in all-optical ring networks

The paper investigates dual-link fault localization in all-optical ring networks using optical probes (called monitoring bursts). By defining a single monitoring node (MN) in the ring that initiates and terminates a set of monitoring trails (m-trails), the MN can localize any dual-link fault by inspecting the on-off status of the launched optical bursts. We investigate relevant problems in the proposed fault monitoring approach, including m-trail allocation, burst launching time scheduling, and node switch fabric configuration, where constructions are developed to derive optimal solutions and are further examined in numerical experiments. 2(|Ej| - 1) m-trails and at most (2δ + L)(|E| - 1) + δ(|E| - 2) of monitoring delay are required for dual-link fault localization from a single MN in a ring with|E| links, where δ is the burst propagation delay along a unidirectional link and L is the burst length.