The Dynamic Trunking Protocol (DTP) is a proprietary link layer protocol developed by Cisco Systems for the purpose of negotiating trunking on a link between two VLAN-aware switches, and for negotiating the type of trunking encapsulation to be used.
VTP communicates VLAN existence information between switches.
DTP aids with trunk port establishment.
Neither protocol transmits the data frames that trunks carry.
[3] Disabling Dynamic Trunking Protocol (DTP).