Cisco Catalyst 3750-X User Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 22 Configuring Optional Spanning-Tree Features
Configuring Optional Spanning-Tree Features
You can also use the spanning-tree bpdufilter enable interface configuration command to enable
BPDU filtering on any interface without also enabling the Port Fast feature. This command prevents the
interface from sending or receiving BPDUs.
Caution Enabling BPDU filtering on an interface is the same as disabling spanning tree on it and can result in
spanning-tree loops.
You can enable the BPDU filtering feature if your switch is running PVST+, rapid PVST+, or MSTP.
Beginning in privileged EXEC mode, follow these steps to globally enable
the BPDU filtering feature.
This procedure is optional.
To disable BPDU filtering, use the no spanning-tr
ee portfast bpdufilter default global configuration
command.
You can override the setting of the no spanning-tr
ee portfast bpdufilter default global configuration
command by using the spanning-tree bpdufilter enable interface configuration command.
Enabling UplinkFast for Use with Redundant Links
UplinkFast cannot be enabled on VLANs that have been configured with a switch priority. To enable
UplinkFast on a VLAN with switch priority configured, first restore the switch priority on the VLAN to
the default value by using the no spanning-tree vlan vlan-id priority global configuration command.
Note When you enable UplinkFast, it affects all VLANs on the switch or switch stack. You cannot configure
UplinkFast on an individual VLAN.
You can configure the UplinkFast or the CSUF feature for rapid PVST+ or for the MSTP, but the feature
remains disabled (inactive) until you change the spanning-tree mode to PVST+.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
spanning-tree portfast bpdufilter default Globally enable BPDU filtering.
By default, BPDU filtering is disabled.
Step 3
interface interface-id Specify the interface connected to an end station, and enter
interface configuration mode.
Step 4
spanning-tree portfast Enable the Port Fast feature.
Step 5
end Return to privileged EXEC mode.
Step 6
show running-config Verify your entries.
Step 7
copy running-config startup-config (Optional) Save your entries in the configuration file.

Cisco Catalyst 3750-X Specifications

General

Brand	Cisco
Model	Catalyst 3750-X
Category	Switch
Language	English