Spanning-Tree Portfast (Interface Configuration) - Cisco ME 3800X Command Reference Manual

spanning-tree portfast (interface configuration)

spanning-tree portfast (interface configuration)
To enable the Port Fast feature on an STP port in all its associated VLANs, use the spanning-tree
portfast command in interface configuration mode. When the Port Fast feature is enabled, the STP port
changes directly from a blocking state to a forwarding state without making the intermediate
spanning-tree state changes. To return to the default setting, use the no form of this command.
Syntax Description disable
trunk
Defaults The Port Fast feature is disabled on all ports.
Command Modes Interface configuration
Command History Release
12.2(52)EY
Usage Guidelines Use this feature only on STP ports that connect to end stations; otherwise, an accidental topology loop
could cause a data packet loop and disrupt switch and network operation.
To enable Port Fast on trunk ports, you must use the spanning-tree portfast trunk interface
configuration command. The spanning-tree portfast command is not supported on trunk ports.
You can enable this feature when the switch is operating in the per-VLAN spanning-tree plus (PVST+),
the rapid-PVST+, or the multiple spanning-tree (MST) mode.
This feature affects all VLANs on the STP port.
An interface with the Port Fast feature enabled is moved directly to the spanning-tree forwarding state
without the standard forward-time delay.
You can use the spanning-tree portfast default global configuration command to globally enable the
Port Fast feature on all nontrunking interfaces. However, the spanning-tree portfast interface
configuration command can override the global setting.
If you configure the spanning-tree portfast default global configuration command, you can disable
Port Fast on an STP port that is not a trunk interface by using the spanning-tree portfast disable
interface configuration command.
You can verify your settings by entering the show running-config privileged EXEC command.
Cisco ME 3800X and ME 3600X Switch Command Reference
-48
spanning-tree portfast [disable | trunk]
no spanning-tree portfast
(Optional) Disables the Port Fast feature on the specified interface.
(Optional) Enables the Port Fast feature on a trunking interface.
Modification
This command was introduced.
Chapter
OL-28238-01