Spanning-Tree Portfast (Interface Configuration) - Cisco ME 3400 Command Reference Manual

Chapter 2 Cisco ME 3400 Ethernet Access Switch Cisco IOS Commands

spanning-tree portfast (interface configuration)

Use the spanning-tree portfast interface configuration command on a network node interface (NNI) or
an enhanced network interface (ENI) on which Spanning Tree Protocol (STP) has been enabled to enable
the Port Fast feature on an STP port in all its associated VLANs. 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. 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 ports.
Command Modes
Interface configuration
Command History Release
12.2(25)EX
Usage Guidelines
STP is not supported on user network interfaces (UNIs). You can enable the spanning-tree Port Fast
feature only on NNIs or on ENIs on which STP has been enabled. To set a port as an NNI or ENI, enter
the port-type {nni | eni} interface configuration command. To enable STP on an ENI, enter the
spanning-tree interface configuration command.
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 NNI 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.
OL-9640-10
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 introduced.
spanning-tree portfast (interface configuration)
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