A VTP domain (also called a VLAN management domain) consists of one controller or several interconnected controllers or controller stacks under the same administrative responsibility sharing the same VTP domain name. A controller can be in only one VTP domain. You make global VLAN configuration changes for the domain.
By default, the controller is in the VTP no-management-domain state until it receives an advertisement for a domain over a trunk link (a link that carries the traffic of multiple VLANs) or until you configure a domain name. Until the management domain name is specified or learned, you cannot create or modify VLANs on a VTP server, and VLAN information is not propagated over the network.
If the controller receives a VTP advertisement over a trunk link, it inherits the management domain name and the VTP configuration revision number. The controller then ignores advertisements with a different domain name or an earlier configuration revision number.
When you make a change to the VLAN configuration on a VTP server, the change is propagated to all controllers in the VTP domain. VTP advertisements are sent over all IEEE trunk connections, including IEEE 802.1Q. VTP dynamically maps VLANs with unique names and internal index associates across multiple LAN types. Mapping eliminates excessive device administration required from network administrators.
If you configure a controller for VTP transparent mode, you can create and modify VLANs, but the changes are not sent to other controllers in the domain, and they affect only the individual controller. However, configuration changes made when the controller is in this mode are saved in the controller running configuration and can be saved to the controller startup configuration file.