Spanning-Tree Portfast (Interface Configuration Mode) - Cisco 4500M Command Reference Manual

spanning-tree portfast (interface configuration mode)

spanning-tree portfast (interface configuration mode)
To enable PortFast mode, where the interface is immediately put into the forwarding state upon linkup
without waiting for the timer to expire, use the spanning-tree portfast command. To return to the
default setting, use the no form of this command.
Syntax Description
disable
trunk
Defaults
PortFast mode is disabled.
Command Modes
Interface configuration
Command History Release
12.1(8a)EW
12.1(12c)EW
Usage Guidelines
You should use this feature only with interfaces that connect to end stations; otherwise, an accidental
topology loop could cause a data packet loop and disrupt the Catalyst4500 series switch and network
operation.
An interface with PortFast mode enabled is moved directly to the spanning tree forwarding state when
linkup occurs without waiting for the standard forward-time delay.
Be careful when using the no spanning-tree portfast command. This command does not disable
PortFast if the
This command has four states:
•
•
•
Note
Catalyst4500 Series SwitchCiscoIOS Command Reference—Release 12.2(18)EW
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spanning-tree portfast {disable | trunk}
no spanning-tree portfast
Disables PortFast on the interface.
Enables PortFast on the interface even while in the trunk mode.
Modification
Support for this command was introduced on the Catalyst 4500 series switch.
The disable and trunk options were added.
spanning-tree portfast default
spanning-tree portfast—This command enables PortFast unconditionally on the given port.
spanning-tree portfast disable—This command explicitly disables PortFast for the given port. The
configuration line shows up in the running-configuration as it is not the default.
spanning-tree portfast trunk —This command allows you to configure PortFast on trunk ports.
If you enter the spanning-tree portfast trunk command, th e port is configured for PortFast
even when in the access mode.
Chapter2 Cisco IOS Commands for the Catalyst 4500 Series Switches
command is enabled.
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