Configuring Advanced Stp Features; Configuring Port Fast - Cisco WS-C3550-12G Software Configuration Manual

Configuring Advanced STP Features

Configuring Advanced STP Features
These sections include advanced STP configuration information:
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Configuring Port Fast

A port with the Port Fast feature enabled is moved directly to the spanning-tree forwarding state without
waiting for the standard forward-time delay.
Caution Use Port Fast only when connecting a single end station to a Layer 2 access port. Enabling this feature
on an interface connected to a switch or hub could prevent STP from detecting and disabling loops
in your network, which could cause broadcast storms and address-learning problems.
Beginning in privileged EXEC mode, follow these steps to enable Port Fast on a Layer 2 access port:
Command
Step 1 configure terminal
Step 2
interface interface-id
Step 3 spanning-tree portfast
Step 4
end
Step 5
show running interface interface-id
Step 6 copy running-config startup-config
To disable the Port Fast feature, use the no spanning-tree portfast interface configuration command.
Catalyst 3550 Multilayer Switch Software Configuration Guide
10-32
Configuring Port Fast, page 10-32
Configuring BPDU Guard, page 10-33
Configuring UplinkFast for Use with Redundant Links, page 10-34
Configuring Cross-Stack UplinkFast, page 10-35
Configuring BackboneFast, page 10-36
Configuring Root Guard, page 10-36
Enabling EtherChannel Guard, page 10-37
Purpose
Enter global configuration mode.
Enter interface configuration mode, and specify an interface to
configure. Valid interfaces include physical interfaces and
port-channel logical interfaces (port-channel
port-channel-number).
Enable Port Fast on a Layer 2 access port connected to a single
workstation or server.
By default, Port Fast is disabled on all interfaces.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Chapter 10 Configuring STP
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