What are the STP times?
- Hello Timer
- Forward delay Timer
- Max-age Timer
- Hello Timer: How often switches send BPDU’s by default every 2 seconds
- Forward delay Timer: how much long a port must spend time in both learning and listening state. By default 15 seconds
- Max-age Timer: How long a switch will retain BPDU information from a neighbor switch before discarding it. By default 20 seconds
Improving STP Convergence
In many environments, a 30 second outage for every topology change is unacceptable. Cisco developed three proprietary features that improve STP convergence time:
- PortFast
- UplinkFast
- BackboneFast