Traditional methods for ensuring reliable transmissions in circuit- switched networks rely on the pre computation of a backup path for every working path or for every network link These methods work fine as long as the network experiences only single link failures. They do not guarantee undisturbed communication, however, in the case of multiple link failures. Such failures are not seldom and often are correlated: a single failure in the physical network (a cut in the conduit carrying wiring or fibers used for several links) results in several failures in the abstract network layer (see for a discussion on multiple link failures).
This type of link failures can be modeled using the notion of generalized failure events. A single generalized failure leads to the failure of several links in the network. Links that belong to the same failure even are also said to be in the same shared risk link group. Recent research has focused on the problem of computing, for a given pair of nodes, two risk-disjoint paths, i.e., two paths that do not share links that belong to the same generalized failure event.
Kumar, Shailesh and SIDDAPPA, M. Dr.
"Reliable Routings in Networks with Generalized Link Failure Events,"
International Journal of Smart Sensor and Adhoc Network: Vol. 1
, Article 10.
Available at: https://www.interscience.in/ijssan/vol1/iss2/10