Allows a port running STP to go directly from blocking to forwarding mode.
This will bypass the 50 second timer (20 seconds max age, 15 seconds listening, 15 seconds learning).
sh spanning-tree interface fastEthernet 0/1 SW(config)#spanning-tree portfast ? bpdufilter Enable portfast bpdu filter on this switch bpduguard Enable portfast bpdu guard on this switch default Enable portfast by default on all access ports SW(config-if)#spanning-tree portfast ? disable Disable portfast for this interface trunk Enable portfast on the interface even in trunk mode <cr>
Switch01 has two paths to the root (sw0) where one is FWD and one is BLCK.
With UplinkFast the port that could potentially reach the rootswitch is collectivly refered as an uplinkgroup (includes FWD and BLCK ports). If the FWD port goes down, the other ports will transition to FWD immediately (between 1-3 seconds).
Not recommended on core and distribuition switches making it “PortFast on the access layer”.
UplinkFast is enabled globally and for all VLANs on the switch.