Cisco Systems 3130 User Manual
19-12
Cisco Catalyst Blade Switch 3130 for Dell Software Configuration Guide
OL-13270-01
Chapter 19 Configuring Optional Spanning-Tree Features
Configuring Optional Spanning-Tree Features
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(optional)
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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.
guard if your switch is running PVST+, rapid PVST+, or MSTP.
You can configure the UplinkFast, the BackboneFast, or the cross-stack UplinkFast feature for rapid
PVST+ or for the MSTP, but the feature remains disabled (inactive) until you change the spanning-tree
mode to PVST+.
PVST+ or for the MSTP, but the feature remains disabled (inactive) until you change the spanning-tree
mode to PVST+.
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.
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.
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
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 19-1
Default Optional Spanning-Tree Configuration
Feature
Default Setting
Port Fast, BPDU filtering, BPDU guard
Globally disabled (unless they are individually configured
per interface).
per interface).
UplinkFast
Globally disabled. (The UplinkFast feature is the CSUF
feature.)
feature.)
BackboneFast
Globally disabled.
EtherChannel guard
Globally enabled.
Root guard
Disabled on all interfaces.
Loop guard
Disabled on all interfaces.