User's Manual

CHAPTER

20-1

Catalyst 3750 Switch Software Configuration Guide

OL-8550-09

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 Chapter 18, “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 19, “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 20-1

• Configuring Optional Spanning-Tree Features, page 20-12

• Displaying the Spanning-Tree Status, page 20-20

Understanding Optional Spanning-Tree Features

These sections contain this conceptual information:

• Understanding Port Fast, page 20-2

• Understanding BPDU Guard, page 20-2

• Understanding BPDU Filtering, page 20-3

• Understanding UplinkFast, page 20-3

• Understanding Cross-Stack UplinkFast, page 20-5

• Understanding BackboneFast, page 20-7

• Understanding EtherChannel Guard, page 20-10