Cisco Systems 3750E manual Enabling UplinkFast for Use with Redundant Links, 20-15

Chapter 20 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.

	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.

To disable BPDU filtering, use the no spanning-tree portfast bpdufilter default global configuration command.

You can override the setting of the no spanning-tree 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-idpriority 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+.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02		20-15