A transmission apparatus executes a reception processing that receives a first alarm detected in a first transmission apparatus different from the own apparatus from among a plurality of transmission apparatus from a second transmission apparatus different from the own apparatus from among the plurality of transmission apparatus, executes a detection processing that detects a second alarm of the own apparatus, executes a mask processing that masks alarms including the first alarm received by the reception processing and the second alarm detected by the detection processing, and executes a sending processing that sends an alarm that is not masked by the mask processing from among the alarms to a third transmission apparatus different from the own apparatus and the second transmission apparatus from among the plurality of transmission apparatus or sending the alarm to a given apparatus different from any of the plurality of transmission apparatus.