CHAPT ER
22-1
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
22
Configuring Optional Spanning-Tree Features
This chapter describes how to configure optional spanning-tree features on the Catalyst 3750-X or
3560-X switch. You can configure all of these features when your switch is running the per-VLAN
spanning-tree plus (PVST+). You can configure only the noted features when your switch or switch stack
is running the Multiple Spanning Tree Protocol (MSTP) or the rapid per-VLAN spanning-tree plus
(rapid-PVST+) protocol. Unless otherwise noted, the term switch refers to a Catalyst 3750-X or 3560-X
standalone switch and to a Catalyst 3750-X switch stack.
For information on configuring the PVST+ and rapid PVST+, see Chapter 20, “Configuring STP. For
information about the Multiple Spanning Tree Protocol (MSTP) and how to map multiple VLANs to the
same spanning-tree instance, see Chapter 21, “Configuring MSTP.”
Note For complete syntax and usage information for the commands used in this chapter, see the command
reference for this release.
This chapter consists of these sections:
Understanding Optional Spanning-Tree Features, page 22-1
Configuring Optional Spanning-Tree Features, page 22-11
Displaying the Spanning-Tree Status, page 22-19

Understanding Optional Spanning-Tree Features

These sections contain this conceptual information:
Understanding Port Fast, page 22-2
Understanding BPDU Guard, page 22-2
Understanding BPDU Filtering, page 22-3
Understanding UplinkFast, page 22-3
Understanding Cross-Stack UplinkFast, page 22-5
Understanding BackboneFast, page 22-7
Understanding EtherChannel Guard, page 22-10
Understanding Root Guard, page 22-10
Understanding Loop Guard, page 22-11