VLAN Trunking Protocol (VTP) is a Cisco proprietary protocol that propagates the definition of Virtual Local Area Networks (VLAN) on the whole local area network. To do this, VTP carries VLAN information to all the switches in a VTP domain.
Important to remember about VTP:
By defaul switch out of the box is in a VTP Server mode
Null domain – default empty domain when VTP is enbled
Doamin name and password are automatically propagated
Support auto-prunning so VLAN not in use are automatically removed from switch
VTPv1/v2 only support VLAN numbers 1-1005
VLAN information are stored in vlad.dat file and wr erase will not remove all VLAN information
Switch with hihest revision number force VLAN update (VTP v1/v2 only)
Primary Server function introduced in VTP v3
VTP v3 introduce OFF mode which will block all VTP updaes passing through the switch
VTP versions comparison
