VLAN Trunking Protocol (VTP) is a Cisco proprietary Layer 2 messaging protocol that manages the addition, deletion, and renaming of VLANs for the Cisco Catalyst Switches in the same VLAN Trunking Protocol (VTP) domain. VLAN Trunking Protocol (VTP) enables Cisco Catalyst Switches to exchange and maintain consistent VLAN information amongst a group of Cisco Catalyst Switches.
For example, information for the VLAN 50 defined in Cisco Catalyst Switch A is propagated via VTP updates to all other Cisco Catalyst Switches (Switches B, C and D) in the same VTP domain, the other Cisco Catalyst Switches B, C and D will all end up adding VLAN 50 in their local VLAN data base. VTP is available on most of the Cisco Catalyst Family products.
The comparable IEEE standard in use by other manufacturers is GVRP.