spanning-tree port type edge

To configure an interface connected to a host as an edge port, which automatically transitions the port to the spanning tree forwarding state without passing through the blocking or learning states, use the spanning-tree port type edge command. To return the port to a normal spanning tree port, use the no spanning-tree port type command.

spanning-tree port type edge [ trunk ]

no spanning-tree port type

Syntax Description

trunk
(Optional) Configures the trunk port as a spanning tree edge port.

Command Default

The default is the global setting for the default port type edge that is configured when you entered the spanning-tree port type edge default command. If you did not configure a global setting, the default spanning tree port type is normal.

Command Modes

Interface configuration mode

Command History

Release
Modification
4.0(0)N1(1a)
This command was introduced.

Usage Guidelines

You can also use this command to configure a port in trunk mode as a spanning tree edge port.


Caution You should use this command only with interfaces that connect to end stations; otherwise, an accidental topology loop could cause a data-packet loop and disrupt the switch and network operation.


When a linkup occurs, spanning tree edge ports are moved directly to the spanning tree forwarding state without waiting for the standard forward-time delay.


Note This is the same functionality that was previously provided by the Cisco-proprietary PortFast feature.


When you use this command, the system returns a message similar to the following:

Warning: portfast should only be enabled on ports connected to a single
host. Connecting hubs, concentrators, switches, bridges, etc... to this
interface when portfast is enabled, can cause temporary bridging loops.
Use with CAUTION
 

When you use this command without the trunk keyword, the system returns an additional message similar to the following:

%Portfast has been configured on Ethernet1/40 but will only
have effect when the interface is in a non-trunking mode.
 

To configure trunk interfaces as spanning tree edge ports, use the spanning-tree port type trunk command. To remove the spanning tree edge port type setting, use the no spanning-tree port type command.

The default spanning tree port type is normal.

Examples

This example shows how to configure an interface connected to a host as an edge port, which automatically transitions that interface to the forwarding state on a linkup:

switch(config-if)# spanning-tree port type edge
 

Related Commands

Command
Description
show spanning-tree
Displays information about the spanning tree state.