VTP Configuration: Cisco 200-125 Exam Guide

ABD

Virtual LAN Trunking Protocol (VTP) is a Cisco proprietary protocol that helps to manage the addition, deletion, and renaming of VLANs on a network-wide basis. When configuring VTP, there are three modes that a Cisco switch can operate in: server, client, and transparent.

Here are the three things that a network administrator should explain to a new technician about VTP configuration:

1. A trunk link must be configured between switches to forward VTP updates.

In a VTP domain, all switches communicate VLAN information with one another through VTP advertisements. VTP advertisements are sent as multicast frames over trunk links between switches that are configured in VTP server or client mode. Therefore, to configure VTP, the network administrator must configure trunk links between the switches to ensure that VTP updates are properly propagated to all switches in the VTP domain.

2. A switch in the VTP server mode will update switches in the VTP client mode regardless of the configured VTP domain membership.

When a switch is configured in VTP server mode, it can create, modify, and delete VLANs in the VTP domain. It then sends VTP advertisements to all other switches in the domain, including switches configured in VTP client mode. The VTP client mode switches can receive and use the VTP advertisements sent by the VTP server mode switches, but they cannot modify the VLAN information themselves. However, a switch in the VTP client mode will update switches in the VTP server mode if it has a higher VTP revision number.

3. A switch in the VTP transparent mode will forward updates that it receives to other switches.

When a switch is configured in VTP transparent mode, it does not participate in VTP updates, and it does not store VLAN information received from other switches. However, it will forward VTP updates to other switches in the VTP domain that are configured in server or client mode. This forwarding behavior helps to ensure that VLAN information is propagated throughout the network, even if some switches are not participating in VTP updates.

It is also important to note that a switch in VTP client mode cannot update its local VLAN database. It relies solely on VTP server mode switches to receive updates to its VLAN database. Additionally, a switch in VTP server mode can update a switch in VTP transparent mode, but a switch in VTP client mode cannot.