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Configuring VTP
Prerequisites for Configuring VTP
When you configure VTP, you must configure a trunk port so that the switch can send and receive VTP
advertisements to and from other switches in the domain.
Before adding a VTP client switch to a VTP domain, always verify that its VTP configuration revision number is lower
than the configuration revision number of the other switches in the VTP domain. Switches in a VTP domain always
use the VLAN configuration of the switch with the highest VTP configuration revision number. If you add a switch that
has a revision number higher than the revision number in the VTP domain, it can erase all VLAN information from the
VTP server and VTP domain. See Adding a VTP Client Switch to a VTP Domain, page 305 for the procedure for
verifying and resetting the VTP configuration revision number.
Restrictions for Configuring VTP
VTP version 1 and VTP version 2 are not interoperable on switches in the same VTP domain. Do not enable VTP
version 2 unless every switch in the VTP domain supports version 2.
In VTP versions 1 and 2, when you configure extended-range VLANs on the switch, the switch must be in VTP
transparent mode. VTP version 3 also supports creating extended-range VLANs in client or server mode.
Information About Configuring VTP
VTP
A VLAN Trunking Protocol (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.
The switch supports 1005 VLANs, but the number of configured features affects the usage of the switch hardware. If the
switch is notified by VTP of a new VLAN and the switch is already using the maximum available hardware resources, it
sends a message that there are not enough hardware resources available and shuts down the VLAN. The output of the
show vlan user EXEC command shows the VLAN in a suspended state.
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