9-9
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-03
Chapter9 Creating and Maintai nin g VLA Ns Using the VLAN Trunking Protocol
Passwords
You can configure a password for the VTP domain, but it is not required. If you do configure a domain
password, all domain switches must share the same password and you must configur e the pa ssword on
each switch in the management domain. Switches without a password or with the wrong password reject
VTP advertisements.
If you configure a VTP password for a domain, a switch that is booted without a VTP configuration does
not accept VTP advertisements until you configure it with the correct password. After the configuration,
the switch accepts the next VTP advertisement that uses the same password and domain name in the
advertisement.
If you are adding a new switch to an existing network with VTP capability, the new switch learns the
domain name only after the applicable password has been con figu red o n it.
Caution When you configure a VTP domain password, the management do main does not function properly if
you do not assign a management domain password to each switch in th e dom a in.
VTP Version
Follow these guidelines when deciding which VTP version to implement:
•All switches in a VTP domain must run the same VTP version.
•A VTP version2-capable switch can operate in the same VTP domain as a switch running VTP
version 1 if version 2 is disabled on the version 2-capable switch (version 2 is disabled by default).
•Do not enable VTP version2 on a switch unless all of the switches in the same VTP domain are
version-2-capable. When you enable version 2 on a switch, all of the v ersion-2-capable switches in
the domain enable version2. If there is a version 1-only switch, it does not exchange VTP
information with switches with version 2 enabled.
•If there are TrBRF and TrCRF Token Ring networks in your environment, you must enable VTP
version 2 for Token Ring VLAN switching to function properly. To run Token Ring and Token
Ring-Net, disable VTP version 2.
•Enabling or disabling VTP pruning on a VTP server enables or disables VTP pruning for the entire
VTP domain.
•Making VLANs pruning-eligible or pruning-ineligible affects pruning eligibility for those VLANs
on that device only (not on all switches in the VTP domain.)
Configuration Requirements
When you configure VTP, you must configure a trunk port so that the switch can send and receive VTP
advertisements. For more information, see the “Understanding VLAN Trunks” section on page9-22.
You can configure VTP by entering commands in the VLAN configuration mode. When you enter the
exit command in VLAN configuration mode, it applies all the com mands tha t yo u e ntere d. VTP
messages are sent to other switches in the VTP domain, and the privilege d EXEC mode prompt appears.
Note The Cisco IOS end and Ctrl-Z commands are not supported in VLAN con fi gu rat ion m od e.
For more configuration guidelines, see the “VLAN Configuration Guidelines” section on page 9-16.