A switch can be a VTP ( VLAN Trunking Protocol ): 

Server: The default VTP role. Servers can create, delete, and rename VLANs. They originate both periodic and triggered VTP advertisements and synchronize their databases with other switches in the domain. 

Client: Clients cannot make VLAN changes. They originate periodic VTP advertisements and synchronize their databases with other switches in the domain. 

Transparent: It can create, delete, and rename VLANs, but its VLANs are only local. It does not originate advertisements or synchronize its database with any other switches. It forwards VTP advertisements out its trunk links, however.  

The two versions of VTP are Version 1 and Version 2. Version 2 has the following added features: 

■ It supports Token Ring VLANs. 

■ Transparent switches pass along messages from both versions of VTP. 

■ Consistency checks are performed only when changes are configured throug the CLI or SNMP.