On identifying SRLG failures in all-optical networks

Neighborhood Failure Localization in All-Optical Networks via Monitoring Trails

“…Such flexibility is desired in an intelligent failure localization framework and cannot be achieved with lengthy m-trails as in the previous studies [2], [3], [17]. Furthermore, short m-trails bear much better physical-layer impairment properties [4] than the previously proposed long m-trails.…”

“…Later, Local Unambiguous Failure Localization (L-UFL) [2], [15]- [17] was introduced, which provides a signaling-free failure restoration framework that can be purely operated in the optical domain. With a set of m-trails properly allocated, a node is L-UFL capable if the node can unambiguously identify any link failure according to locally available m-trail on-off status.…”

“…This is due to the sharing of on-off status information among the nodes traversed by a common m-trail. Motivated by the preceding result, similar ideas were developed in [17] via a novel heuristic approach, and were further extended in [2] in which all the nodes are made L-UFL capable under any single link failure. An efficient heuristic was developed for allocating m-trails in a shape of spanning tree via link code swapping.…”

“…Thus, the affected W-LP can be switched over to the P-LP without waiting for the cross-layer signaling mechanisms as in GMPLS. Although technically sound, [2], [3], [17] used very lengthy m-trails to localize all link failures at each node. This is not considered feasible in some cases, which is the last hurdle of the practical implementation of NWL-ULF.…”

“…3) Coverlength: is the total number of WLs taken by the m-trails, which has been taken as the metric to evaluate the mtrail solutions [2], [15]- [17], and will still be the performance measure of this study.…”