What is VTP?
VTP (VLAN Trunking Protocol) is a Cisco proprietary protocol used by Cisco switches to exchange VLAN information. VTP is used to synchronize VLAN information (Example:-VLAN ID or VLAN Name) with switches inside the same VTP domain.
What are different VTP modes?
VTP Server mode - By default every switch is in server mode. Switch in VTP Server Mode can create, delete VLANs and will propagate VLAN changes.
VTP Client mode - Switch in VTP client mode cannot create or delete VLANs. VLAN Trunking Protocol (VTP) client mode switches listen to VTP advertisements from other switches and modify their VLAN configurations accordingly. It listens and forwards updates.
VTP Transparent mode - Switch in VTP Transparent mode does not share its VLAN database but it forwards received VTP advertisements. we can create and delete VLANs on a VTP transparent switch but these changes are not sent to other switches.
What are the requirements to exchange VTP messages between two switches?
1.Switch should be configured as either a VTP server or VTP client.
2.VTP domain name must be same on both switches.
3.VTP versions must match.
4.Link between the switches should be a trunk link.
What is VTP Pruning ?
VLAN Trunking Protocol (VTP) pruning is a feature in Cisco switches, which stops VLAN update information traffic from being sent down trunk links if the updates are not needed. Broadcast frames, multicast frames or unicast frames for which the destination MAC address is unknown are forwarded over a trunk link only if the switch on the receiving end of the trunk link has ports in the source VLAN. This avoids unnecessary flooding. VLAN 1 can never prune because it’s an administrative VLAN.