CHAPT ER
20-1
Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
20
Configuring Optional Spanning-Tree Features
This chapter describes how to configure optional spanning-tree features on the Catalyst 3750 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 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 standalone switch and to a switch stack.
For information on configuring the PVST+ and rapid PVST+, see Chapter18, “Configuring STP.” For
information about the Multiple Spanning Tree Protocol (MSTP) and how to map multiple VLANs to the
same spanning-tree instance, see Chapter19, “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, page20-1
Configuring Optional Spanning-Tree Features, page20-12
Displaying the Spanning-Tree Status, page20-20

Understanding Optional Spanning-Tree Features

These sections contain this conceptual information:
Understanding Port Fast, page20-2
Understanding BPDU Guard, page20-2
Understanding BPDU Filtering, page20-3
Understanding UplinkFast, page20-3
Understanding Cross-Stack UplinkFast, page20-5
Understanding BackboneFast, page20-7
Understanding EtherChannel Guard, page 20-10