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 VTP
This chapter describes how to use the VLAN Trunking Protocol (VTP) and the VLAN database for
managing VLANs with the Catalyst 3750-X or 3560-X switch. 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.
Note For complete syntax and usage information for the commands used in this chapter, see the command
reference for this release.
The chapter consists of these sections:
•
Understanding VTP, page 1-1
• Configuring VTP, page 1-8
•
Monitoring VTP, page 1-18
Understanding VTP
VTP is a Layer 2 messaging protocol that maintains VLAN configuration consistency by managing the
addition, deletion, and renaming of VLANs on a network-wide basis. VTP minimizes misconfigurations
and configuration inconsistencies that can cause several problems, such as duplicate VLAN names,
incorrect VLAN-type specifications, and security violations.
Before you create VLANs, you must decide whether to use VTP in your network. Using VTP, you can
make configuration changes centrally on one or more switches and have those changes automatically
communicated to all the other switches in the network. Without VTP, you cannot send information about
VLANs to other switches.
VTP is designed to work in an environment where updates are made on a single switch and are sent
through VTP to other switches in the domain. It does not work well in a situation where multiple updates
to the VLAN database occur simultaneously on switches in the same domain, which would result in an
inconsistency in the VLAN database.
VTP functionality is supported across the stack, and all switches in the stack maintain the same VLAN
and VTP configuration inherited from the stack master. When a switch learns of a new VLAN through
VTP messages or when a new VLAN is configured by the user, the new VLAN information is
communicated to all switches in the stack.
When a switch joins the stack or when stacks merge, the new switches get VTP information from the
stack master.