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Catalyst 3750 Metro Switch Command Reference
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Chapter 2 Catalyst 3750 Metro Switch Cisco IOS Commands
spanning-tree portfast (interface configuration)
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.
spanning-tree portfast
[
disable
|
trunk
]
no spanning-tree portfast
Syntax Description
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
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 plus (PVST+),
the rapid-PVST+, or the multiple spanning-tree (MST) mode.
This feature affects all VLANs on the port.
An interface with the Port Fast feature enabled moves 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 enable Port
Fast on an interface that is not a trunk interface 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.
disable
(Optional) Disable the Port Fast feature on the specified interface.
trunk
(Optional) Enable the Port Fast feature on a trunking interface.
Release
Modification
12.1(14)AX
This command was introduced.