| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and the like that observe an UPDATE message based on BGP by a normal sequence and can determine an actually occurred faulty link in real time.SOLUTION: An observation node device includes: a first step of recording a path through which a received UPDATE message passes and detecting a faulty node device candidate or faulty link candidate the number of prefixes of which is zero; a second step of determining existence or non-existence of a roundabout link other than the faulty link candidate regarding the faulty node device candidate according with an upstream side node device of the faulty link candidate; and a third step of, in the case of existence of the roundabout link, determining that a fault has occurred on the faulty link candidate if the UPDATE message with a prefix for which the faulty node device candidate is a notification source has arrived, and on the contrary, determining that a fault has occurred at the faulty node device candidate if the UPDATE message with the prefix has not arrived. |
