| 主权项 |
1. A transmission apparatus that switches to a line of one standby system upon occurrence of a fault on any one of n lines of a working system, comprising:
a switching controller that when switching from a line of the working system to a line of the standby-system upon the occurrence of the fault and executing a given command to put the line causing the fault in a given state of line switching according to the given command, causes the working system to maintain the state of line switching according to the given command even after restoration from the fault, wherein the given command is one of a plurality of commands conforming to a prescribed communication standard and having a priority corresponding to a level of the fault, and the switching controller has set therein a definition of advanced manual switch that has a priority between manual switch and forced switch defined as a command having a higher priority than the manual switch, the switching controller further maintains and reports the state of the line switching as the manual switch to a destination external to the transmission apparatus while bringing about, inside the transmission apparatus, a state of line switching having a higher fault level than the manual switch; wherein the commands are set in descending order of priority including the forced switch>SF (high)>the advanced manual switch+SF (signal fail-high)>SF (low)>the advanced manual switch+the SF (low)>SD (signal degrade-high)>the advanced manual switch+SD (high)>SD (low)>the advanced manual switch+the SD (low)>the manual switch, where terms subsequent to “+” represent states reported to the destination external to the transmission apparatus; and wherein the switching controller, after execution of a command for the manual switch on the line causing the fault, if a fault having a higher priority occurs, makes transition to a state equivalent to the fault having the higher priority. |
