Scientific Research Publishing
Internet Service Providers (ISPs) have an obligation to observe the conditions set in the Service Level Agreements (SLA) with their customers. One of the conditions is to ensure that ISPs minimize the duration of the loss of connectivity. Losses of connectivity are common occurrences most especially in networks with larger topologies, although most of the times such losses of connectivity are unavoidable as the ISPs have to shut down the equipment for them to be able to conduct the scheduled routine maintenance. The link metric of a link can always be increased to a larger metric by progressively increasing the metric of the link by one, until the target metric is reached.