STP default timers

STP default timers
Blocking
BPDU aging
Listening
Learning
20 seconds
15 seconds
+ 15 seconds
Total = 50 seconds
Spanning Tree Operation 493
Notice the time from blocking to forwarding. Blocking to listening is 20 seconds (BPDU
aging). Listening to learning is another 15 seconds (listening). Learning to forwarding is
15 seconds (learning), for a total of 50 seconds. However, the switch could go to disabled
if the port is administratively shut down or the port has a failure.