| 摘要 |
PROBLEM TO BE SOLVED: To provide a network monitoring device, a network monitoring system, and a network monitoring method, capable of effectively reducing a load of monitoring processing.SOLUTION: A network monitoring device determines that a session in which a response message corresponding to a request message is not detected within a limit time from a detection time of the request message, among one or more monitoring target sessions, is abnormal. The network monitoring device comprises: a periodic processing unit periodically determining whether or not the response message is detected for each of the one or more sessions, and activating a timer that expires by an elapse of the limit time for such a session that the limit time is elapsed until the next determination processing is performed, among sessions in which no response message is detected; and a determination processing unit determining the session as abnormal in a case where no response message is detected when the timer expires. |
