Name: Cisco 4500M
Brand: Cisco
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Catalyst4500 Series SwitchCiscoIOS Command Reference—Release 12.2(18)EW

78-16201-01

Chapter2Cisco IOS Commands for the Catalyst 4500 Series Switches

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.

spanning-tree portfast {disable | trunk}

no spanning-tree portfast

Syntax Description

Defaults PortFast mode is disabled.

Command Modes Interface configuration

Command History

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 spanning-tree portfast default command is enabled.

This command has four states:

• 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.

Note If you enter the spanning-tree portfast trunk command, the port is configured for PortFast

even when in the access mode.

disable Disables PortFast on the interface.

trunk Enables PortFast on the interface even while in the trunk mode.

Release Modification

12.1(8a)EW Support for this command was introduced on the Catalyst 4500 series switch.

12.1(12c)EW The disable and trunk options were added.

Cisco 4500M Command Reference

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