Administrator Guide

Layer 2 Switching Commands 772
Bridge priority configuration is given preference over the root
primary/secondary configuration. Root primary/secondary configuration is
given preference over the DRC configuration.
The switch with the lowest priority is selected as the root of the spanning tree.
Example
The following example configures the spanning tree priority of instance 1 to
4096.
console(config)#spanning-tree mst 1 priority 4096
spanning-tree portfast
Use the spanning-tree portfast command in Interface Configuration mode to
enable portfast mode. In portfast mode, the interface is immediately put into
the forwarding state upon linkup, without waiting for the timer to expire. To
disable portfast mode, use the no form of this command.
Syntax
spanning-tree portfast
no spanning-tree portfast
Default Configuration
Portfast mode is disabled.
Command Mode
Interface Configuration (gigabitethernet, port-channel, tengigabitethernet,
fortygigabitethernet) mode
User Guidelines
This command only applies to access ports. The command is to be used only
with interfaces connected to end stations. Otherwise, an accidental topology
loop could cause a data packet loop and disrupt switch and network
operations.
An interface with portfast mode enabled is moved directly to the spanning
tree forwarding state when linkup occurs without waiting the standard
forward-time delay.