Spanning-Tree Portfast (Interface Configuration) - Cisco Catalyst 2950 Command Reference Manual

Chapter 2 Cisco IOS Commands

spanning-tree portfast (interface configuration)

Use the spanning-tree portfast interface configuration command to enable the Port Fast feature on an
interface in all its associated VLANs. When the Port Fast feature is enabled, the interface changes
directly from a blocking state to a forwarding state without making the intermediate spanning-tree state
changes. Use the no form of this command to return to the default setting.
Syntax Description
disable
trunk
Defaults The Port Fast feature is disabled on all interfaces; however, it is automatically enabled on
dynamic-access ports.
Command Modes
Interface configuration
Command History Release
12.0(5.2)WC(1)
12.1(9)EA1
Usage Guidelines
Use this feature only on interfaces that connect to end stations; otherwise, an accidental topology loop
could cause a data packet loop and disrupt switch and network operation.
You can enable this feature when the switch is operating in the per-VLAN spanning-tree (PVST) or the
multiple spanning-tree (MST) mode.
This feature affects all VLANs on the interface.
A port with the Port Fast feature enabled is moved directly to the spanning-tree forwarding state without
waiting 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 enable Port
Fast on a port that is not a trunk port by using the no spanning-tree portfast interface configuration
command.
The no spanning-tree portfast interface configuration command is the same as the spanning-tree
portfast disable interface configuration command.
78-11381-05
spanning-tree portfast [disable | trunk]
no spanning-tree portfast
(Optional) Disable the Port Fast feature on the specified interface.
(Optional) Enable the Port Fast feature on a trunking interface.
Modification
This command was first introduced.
The disable and trunk keywords were added.
spanning-tree portfast (interface configuration)
Catalyst 2950 Desktop Switch Command Reference
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