Patent ID: 8774025

Claim:
A method for judging delivery status of a push signal, the method comprising: receiving packets flowing in a specific session between a transmission source and transmission destination at an arbitrary point on a route of the specific session, and storing the received packets into a storage device, wherein the packets include voice packets and non-voice packets representing the push signal; first judging based on sequence numbers included in the received packets stored in the storage device, whether or not packet loss has occurred in the specific session; and upon detecting that the packet loss has occurred, second judging, according to at least one of first to third properties, whether or not loss of the push signal has occurred, wherein the first property includes time difference between the packet immediately before the lost packets and the packet immediately after the lost packets, the second property includes transmission intervals of the voice packets and the non-voice packets, and the third property includes the minimum number of non-voice packets used to represent one push signal, and the second judging comprises: comparing the minimum number of non-voice packets used to represent the one push signal with the number of lost packets or the number of remaining packets identified by excluding packets presumed as the non-voice packets from the lost packets; and upon detecting that the number of lost packets or the number of remaining packets is less than the minimum number of non-voice packets used to represent the one push signal, determining that loss of the push signal has not occurred.