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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
OL-12247-04
Chapter 20 Configuring Optional Spanning-Tree Features
Configuring Optional Spanning-Tree Features
Beginning in privileged EXEC mode, follow these steps to enable Port Fast. This procedure is optional.
Note
You can use the
spanning-tree portfast default
global configuration command to globally enable the
Port Fast feature on all nontrunking ports.
To disable the Port Fast feature, use the
spanning-tree portfast disable
interface configuration
command.
Enabling BPDU Guard
When you globally enable BPDU guard on ports that are Port Fast-enabled (the ports are in a Port
Fast-operational state), spanning tree continues to run on the ports. They remain up unless they receive
a BPDU.
In a valid configuration, Port Fast-enabled ports do not receive BPDUs. Receiving a BPDU on a Port
Fast-enabled port means an invalid configuration, such as the connection of an unauthorized device, and
the BPDU guard feature puts the port in the error-disabled state. When this happens, the switch shuts
down the entire port on which the violation occurred.
To prevent the port from shutting down, you can use the
errdisable detect cause bpduguard shutdown
vlan
global
configuration
command to shut down just the offending VLAN on the port where the
violation occurred.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface
interface-id
Specify an interface to configure, and enter interface
configuration mode.
Step 3
spanning-tree portfast
[
trunk
]
Enable Port Fast on an access port connected to a single
workstation or server. By specifying the
trunk
keyword, you can
enable Port Fast on a trunk port.
Note
To enable Port Fast on trunk ports, you must use the
spanning-tree portfast
trunk
interface configuration
command. The
spanning-tree portfast
command will
not work on trunk ports.
Caution
Make sure that there are no loops in the network
between the trunk port and the workstation or server
before you enable Port Fast on a trunk port.
By default, Port Fast is disabled on all interfaces.
Step 4
end
Return to privileged EXEC mode.
Step 5
show spanning-tree interface
interface-id
portfast
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.