
C H A P T E R
16-1
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-09
16
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
Chapter 17, “Configuring MSTP.”
For information about other spanning-tree features such as Port Fast, UplinkFast, root guard, and so
forth, see
Chapter 18, “Configuring Optional Spanning-Tree Features.”
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:
•
Understanding Spanning-Tree Features, page 16-1
•
Configuring Spanning-Tree Features, page 16-11
•
Displaying the Spanning-Tree Status, page 16-24
Understanding Spanning-Tree Features
These sections describe how basic spanning-tree features work:
•
•
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
•