Cisco Catalyst 3550 Series - Configuring Optional Spanning-Tree Features

18-14
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-09
Chapter 18 Configuring Optional Spanning-Tree Features
Configuring Optional Spanning-Tree Features
Configuring Optional Spanning-Tree Features
These sections describe how to configure optional spanning-tree features:
• Default Optional Spanning-Tree Configuration, page 18-14
• Optional Spanning-Tree Configuration Guidelines, page 18-14
• Enabling Port Fast, page 18-14 (optional)
• Enabling BPDU Guard, page 18-15 (optional)
• Enabling BPDU Filtering, page 18-16 (optional)
• Enabling UplinkFast for Use with Redundant Links, page 18-17 (optional)
• Enabling Cross-Stack UplinkFast, page 18-19 (optional)
• Enabling BackboneFast, page 18-20 (optional)
• Enabling EtherChannel Guard, page 18-20 (optional)
• Enabling Root Guard, page 18-21 (optional)
• Enabling Loop Guard, page 18-21 (optional)
Default Optional Spanning-Tree Configuration
Table 18-1 shows the default optional spanning-tree configuration.
Optional Spanning-Tree Configuration Guidelines
The UplinkFast, BackboneFast, and cross-stack UplinkFast features are not supported with the rapid
PVST+ or the MSTP.
Enabling 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.
Table 18-1 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.
CSUF Disabled on all interfaces.
BackboneFast Globally disabled.
EtherChannel guard Globally enabled.
Root guard Disabled on all interfaces.
Loop guard Disabled on all interfaces.