VLAN Trunking Protocol (VTP)

The article defined and described in the section is the VLAN (Virtual Local Area Network) trunking protocol (VTP). What is a VLAN trunking protocol (VTP)? What are its uses? All of these questions are answered in this section. Reading the entire article will give you an overview of the topic.

VLAN Trunking Protocol (VTP) is a proprietary protocol introduced by the Cisco team. In the Local Area Network (LAN) the idea about VLAN (Virtual Local Area Network) is spread by this protocol named VTP. To spread the information about the VLAN, the VTP carries and the information’s to the switches in the VTP (VLAN Trunking Protocol) domain.

The different versions of the VTP introduced are version 1, version 2, and version 3. One of the advantages of using the VTP  is they consist of two-layer frames that are easy to add, delete or rename the VLAN information from the VLAN client mode.

When new VLANs (Virtual Local Area Network) are added plug and play configuration is used. Across the network, the VLANs can be get distributed dynamically. The VLAN information is also get synchronized by the VTP (VLAN Trunking Protocol).

The role of the network administrator gets reduced in the VTP. The advertisements of the VTP are sent to ISL (Inter Switched Link) trunk and the 802.1Q. The VLAN  information gets communicated through the VTP requires certain requirements. They are mentioned in below part as point wise:

  1. The switch that needs to configure by the user must be of the same version of the VTP (VLAN Trunking Protocol).
  2. Domain name should be the same on the switch and the VTP.
  3. Among all switch one is a server.
  4. If the matches occur then authentication need to be used.

VTP (VLAN Trunking Protocol) contains 3 modes and is explained in the below part. They are:

  • Server
  • Client
  • Transparent

Server mode: – By default, switches are sent to this mode. In this mode, we can create the VLANs, add the VLANs, and delete the VLANs. If we need to change anything then it needs to be done in this mode. If any changes are done in this mode then this mode will advertise the changes to all the switches in the same VTP  domain. In NVRAM the configurations are saved from this mode.

Client mode: – In the client mode, switches can receive the updated information and can forward the updates to other switches. Updates are not saved in NVRAM. If the switch reset then the information will be deleted. The switches in this mode only transfer the summary of VTP to other switches.

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Transparent mode: – Only by using the trunk link the VTP summary is forwarded in this mode. This mode can make their local database and they keep a secret from other switches. The main purpose of transparent mode they forward VTP summary but not a part of the VLAN assignment.