Portfast

The best practice is to configure this on every port connected to hosts.

• Hosts and end devices
• Transition to forwarding faster
• Do not send TCN BPDUs

Note

This stops TCNs, which cause the max-age timer to reduce to the duration of the forward delay on receipt of a TCN.

Hosts wich require Portfast

• PXE
• DHCP

The minimum time for 802.1D is 30 seconds, (2x the forwarding delay).

This means some computers will miss DHCP, and sometimes PXE fails.

Config

Enable on all access ports

spanning-tree portfast default

Enable on trunks

Some trunk ports connect to servers. Portfast can be enabled on those too.

spanning-tree portfast trunk