| 摘要 |
PROBLEM TO BE SOLVED: To allow an end terminal that belongs to a home network to determine whether another end terminal belonging to the same network is in an active or standby state without the need of implementing a specific protocol function in the end terminal.SOLUTION: An end terminal 10 supporting protocols such as ICMP and HTIP stores therein device names received from other end terminals 20 and 21. The terminal 10 retrieves from a predetermined database: an average RTT (Ton) value when the terminal 10 sending Pings using its available communication processing capability to the terminal 20 that is in an active state; an average RTT (Tst) value obtained in the same way as the average RTT (Ton), except that the terminal 20 is in a standby state; &sgr;on and &sgr;st that are the standard deviations of these values; and the length of time (Tsl) it takes for the terminal 20 to transition from an active state to a standby state. The terminal 10 sends a Ping to the terminal 20 three times at intervals of (Tsl+1) seconds, measures the second RTT (Tr) and the third RTT (T), and makes the determination on the basis of |(T-Tnw)-(Ton+&sgr;on)|>| (T-Tnw)-(Tst+&sgr;st)|. |
