VLAN Trunking Protocol
VTP sends messages between trunked switches to maintain VLANs on these switches in order to properly trunk.
VTP is a Cisco proprietary method of managing VLANs between switches and runs across any type of trunking mechanism.
VTP messages are exchanged between switches within a common VTP domain.
VTP domains must be defined or VTP disabled before a VLAN can be created.
Exchanges of VTP information can be controlled by passwords.
VTP manages only VLANs 2 through 1002.
VTP allows switches to synchronize their VLANs based on a configuration revision number.
Switches can operate in one of three VTP modes: server, transparent, or client.
VTP can prune unneeded VLANs from trunk links.