Cisco WS-C4003 - Catalyst 4000 Chassis Switch Software Configuration Manual page 97

Configuring Spanning Tree
This chapter provides a brief overview of the IEEE 802.1D bridge Spanning Tree Protocol (STP) and
describes how to use and configure Cisco's proprietary Spanning Tree Protocols, Per VLAN Spanning
Tree + (PVST+), and Multi-Instance Spanning Tree Protocol (MISTP) on the Catalyst enterprise LAN
switches.
Note For information on configuring the spanning tree PortFast, UplinkFast, and BackboneFast features, see
Chapter 8, "Configuring Spanning Tree PortFast, UplinkFast, and BackboneFast, and Loop Guard."
This chapter consists of these sections:
•
•
•
•
•
•
•
•
Note For complete syntax and usage information for the commands used in this chapter, refer to the Command
Reference—Catalyst 4000 Family, Catalyst 2948G, and Catalyst 2980G Switches.
How Spanning Tree Protocols Work
This section describes the specific functions that are common to all spanning tree protocols. Cisco's
proprietary spanning tree protocols, PVST+ and MISTP, are based on the IEEE 802.1D STP. (See the
"Understanding PVST+ and MISTP Modes" section on page 7-10
MISTP.) The 802.1D STP is a Layer 2 management protocol that provides path redundancy in a network
while preventing undesirable loops. All spanning tree protocols use an algorithm that calculates the best
loop-free path through the network.
78-12647-02
How Spanning Tree Protocols Work, page 7-1
Understanding PVST+ and MISTP Modes, page 7-10
Bridge Identifiers, page 7-12
Using PVST+, page 7-12
Using MISTP-PVST+ or MISTP, page 7-18
Configuring a Root Switch, page 7-27
Configuring Spanning Tree Timers, page 7-30
Configuring Spanning Tree BPDU Skewing, page 7-33
Software Configuration Guide—Catalyst 4000 Family, Catalyst 2948G, Catalyst 2980G, Releases 6.3 and 6.4
C H A P T E R
for information about PVST+ and
7
7-1