Understanding Spanning-Tree Features - Cisco Catalyst 3550 series Software Configuration Manual

Configuring STP
This chapter describes how to configure the Spanning Tree Protocol (STP) on port-based VLANs on
your Catalyst 3550 switch. The switch uses the per-VLAN spanning-tree plus (PVST+) protocol based
on the IEEE 802.1D standard and Cisco proprietary extensions, or it can use the rapid per-VLAN
spanning-tree plus (rapid-PVST+) protocol based on the IEEE 802.1W standard.
For information about the Multiple Spanning Tree Protocol (MSTP) and how to map multiple VLANs
to the same spanning-tree instance, see
For information about other spanning-tree features such as Port Fast, UplinkFast, root guard, and so
forth, see
Note For complete syntax and usage information for the commands used in this chapter, refer to the command
reference for this release.
This chapter consists of these sections:
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Understanding Spanning-Tree Features

These sections describe how basic spanning-tree features work:
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Chapter 18, "Configuring Optional Spanning-Tree Features."
Understanding Spanning-Tree Features, page 16-1
Configuring Spanning-Tree Features, page 16-11
Displaying the Spanning-Tree Status, page 16-24
STP Overview, page 16-2
Spanning-Tree Topology and BPDUs, page 16-2
Bridge ID, Switch Priority, and Extended System ID, page 16-3
Spanning-Tree Interface States, page 16-4
How a Switch or Port Becomes the Root Switch or Root Port, page 16-7
Spanning Tree and Redundant Connectivity, page 16-7
Spanning-Tree Address Management, page 16-8
Accelerated Aging to Retain Connectivity, page 16-8
Spanning-Tree Modes and Protocols, page 16-9
Supported Spanning-Tree Instances, page 16-9
C H A P T E R
Chapter 17, "Configuring MSTP."
Catalyst 3550 Multilayer Switch Software Configuration Guide
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