Setting the PTP Timeout Interval

To set the timeout multiplier for an interface, use the ptp announce timeout command. The timeout multiplier is the number of announcement intervals that the interface will wait without receiving a PTP announcement before a timeout occurs; values range from 2 to 255. The default multiplier is 3, which results in a 6-second timeout interval when the announcement interval is set to the default of 2 seconds.

This command sets timeout multiplier for the interface to 5; since the announcement interval has just been set to 2 (4 seconds), this means the interface will time out if it doesnt receive a PTP announcement for 20 seconds.
switch(config-if-Et5)# ptp announce timeout 5
switch(config-if-Et5)#