Method, node device, and program for detecting faulty link in real time based on routing protocol

摘要

A method is disclosed of detecting a failed link in a network over which nodes are interconnected via links. The nodes include an observer node and a managed node. This method, implemented for the observer node, includes: determining, for each of prefixes in receive route-update messages, a single normal-state path; determining, for each of the links (i.e., monitored links) on the normal-state path for the managed node, at least one prefix advertised from one of the nodes which is located adjacent to the each link on an upstream side, as at least one monitored prefix; determining whether the path contained in each route-update message, and the normal-state path for the monitored prefix contained in the each route-update message are unmatched with each other; counting, for each monitored link, an unmatched-prefix count which refers to a count of at least one unmatched prefix of the at least one monitored prefix for each monitored link; and extracting at least one link from the monitored links, as at least one failed link, based on the unmatched-prefix count.