Cisco Catalyst 3560-X Series, Software Configuration Manual

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C H A P T E R
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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-25303-03
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Configuring STP
This chapter describes how to configure the Spanning Tree Protocol (STP) on port-based VLANs on the
Catalyst 3750-X or 3560-X switch. The switch can use either the per-VLAN spanning-tree plus (PVST+)
protocol based on the IEEE 802.1D standard and Cisco proprietary extensions, or the rapid per-VLAN
spanning-tree plus (rapid-PVST+) protocol based on the IEEE 802.1w standard. A switch stack appears
as a single spanning-tree node to the rest of the network, and all stack members use the same bridge ID.
Unless otherwise noted, the term
switch refers to a Catalyst 3750-X or 3560-X standalone switch and to
a Catalyst 3750-X switch stack.
For information about the Multiple Spanning Tree Protocol (MSTP) and how to map multiple VLANs
to the same spanning-tree instance, see
Chapter 1, “Configuring MSTP.” For information about other
spanning-tree features such as Port Fast, UplinkFast, root guard, and so forth, see Chapter 1,
“Configuring Optional Spanning-Tree Features.”
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 Spanning-Tree Features, page 1-1
•
Configuring Spanning-Tree Features, page 1-13
• Displaying the Spanning-Tree Status, page 1-25
Understanding Spanning-Tree Features
These sections contain this conceptual information:
•
STP Overview, page 1-2
• Spanning-Tree Topology and BPDUs, page 1-3
•
Bridge ID, Switch Priority, and Extended System ID, page 1-5
• Spanning-Tree Interface States, page 1-5
•
How a Switch or Port Becomes the Root Switch or Root Port, page 1-8
• Spanning Tree and Redundant Connectivity, page 1-9
•
Spanning-Tree Address Management, page 1-9
• Accelerated Aging to Retain Connectivity, page 1-9