| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the time till communication restart after the confirmation of recovery of a link state from an abnormal state to a normal state. SOLUTION: A 1st or a 2nd state inquiry message SE/SE-F is sent at each prescribed time interval, a 1st state display message S corresponding to the 1st state message SE is received to confirm a link state and a 2nd state display message S-F corresponding to the 2nd message SE-F is received to confirm a link state and a PVC(permanent virtual circuit) state. Then a prescribed time interval is set between a normal link state and an abnormal link state, a different transmission interval of the 2nd state inquiry message SE-F is set between the normal and abnormal link states, and the 2nd state inquiry message SE-F is sent at the abnormal state time interval and transmission interval in the case of the abnormal state and the 2nd state display message S-F corresponding to the inquiry is received.</p> |
