| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect the occurrence of a fault, to notify a counter transmission apparatus thereof, to perform control so as not to fall into an infinite loop state and to stably and surely recover a system when the fault is recovered. <P>SOLUTION: Network apparatuses 1, 2 are connected via a plurality of transmission apparatuses 3, 4 and when a line disconnection between the network apparatus 2 and the transmission apparatus 4 is detected by the transmission apparatus 4, it is reported to the transmission apparatus 3 by a maintenance frame. The transmission apparatus 3 judges forced link cut to the network apparatus 1 and sends a link cut transfer starting frame to the transmission apparatus 4, and the transmission apparatus 4 prohibits the forced link cut with respect to the network apparatus 2 and when the line disconnection recovery is detected, it is reported to the transmission apparatus 3 by the maintenance frame. The transmission apparatus 3 cancels the forced link cut to the network apparatus 1 and sends a link cut transfer ending frame to the transmission apparatus 4, and the transmission apparatus 4 turns the state with the network apparatus 2 into an ordinary state. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
