20-12
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
•
Enabling BackboneFast, page 20-16
(optional)
•
Enabling EtherChannel Guard, page 20-17
(optional)
•
Enabling Root Guard, page 20-18
(optional)
•
Enabling Loop Guard, page 20-18
(optional)
Default Optional Spanning-Tree Configuration
shows the default optional spanning-tree configuration.
Optional Spanning-Tree Configuration Guidelines
You can configure PortFast, BPDU guard, BPDU filtering, EtherChannel guard, root guard, or loop
guard if your switch is running PVST+, rapid PVST+, or MSTP.
Enabling Port Fast
An interface 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 an access or trunk port. Enabling this feature
on an interface connected to a switch or hub could prevent spanning tree from detecting and disabling
loops in your network, which could cause broadcast storms and address-learning problems.
If you enable the voice VLAN feature, the Port Fast feature is automatically enabled. When you disable
voice VLAN, the Port Fast feature is not automatically disabled. For more information, see
You can enable this feature if your switch is running PVST+, rapid PVST+, or MSTP.
Table 20-1
Default Optional Spanning-Tree Configuration
Feature
Default Setting
Port Fast, BPDU filtering, BPDU guard
Globally disabled (unless they are individually configured
per interface).
UplinkFast
Globally disabled. (On stacking-capable switches, the
UplinkFast feature is the CSUF feature.)
BackboneFast
Globally disabled.
EtherChannel guard
Globally enabled.
Root guard
Disabled on all interfaces.
Loop guard
Disabled on all interfaces.