How to configure VTP version 2? What is VTP?

Let’s understand VTP with an example when you have a network with 30 switches and 50 VLANs. Normally you have to configure each and every switch separately and create VLANs on each and every switch in your network. Yes it’s a time consuming task so here comes VTP (VLAN Trunking Protocol) to help us. VTP will help us to create VLANs on one switch and all the other remaining switches will synchronize themselves. VTP manages the addition, deletion and renaming of VLAN across the network from a focal point of control.

VLAN Trunking Protocol (VTP) is a Cisco proprietary protocol, as I already said VTP is used to share the VLAN configuration with other switches and maintain consistency throughout that network but information will be passed only if the switch is connected with fast Ethernet or higher ports and also it must be trunk links.

VTP modes:
Server mode is a default mode and have full control over VLAN, it can creation, deletes and modifies VLANs configuration and synchronizes VLAN configurations, server mode which is by default mode it can sends and forwards advertisements

Client mode this mode doesn’t store its VLAN configuration information in the NVRAM. Instead, it learn from the server each time when its boots up. VTP client mode do not allow administrator to create, delete, and modify any VLAN configurations, client mode is able to forwards advertisements and its synchronize VLAN configurations but as I said, client mode do not save VLAN configuration in NVRAM.

Transparent mode is can add VLAN, modify and as well it’s delete also VLAN configuration locally transparent mode does not synchronize VLAN configurations. It forward advertisements and this mode saves its VLANs configuration in NVRAM.
Revision number
VTP switch use an index called the VTP configuration revision number to keep track of the most recent information. The VTP advertisement process always starts with configuration revision number 0. When subsequent change is made on VTP server, the revision number is incremented before the advertisements are sent.

Note: before adding a switch to an existing VTP domain, make sure your switch has VTP Revision number is set 0 before adding in to network. For best practice change switch VTP transparent mode and then back to server mode, change the switch VTP domain name to a non-exist VTP domain and then change it back to original name.
VTP version:-
There are three VTP versions are available:-

VTP version 1 supports only one VTP domain. VTP version 1 check for domain name, if VTP domain matches then only its forward VTP messages. Its do not support token ring VLAN.

VTP version 2 support multiple VTP domain , its check for consistency, every time when new information is added but the major difference between version 1 and 2 is version 2 support Token ring VLAN.

VTP version 3 is having feature of VTP primary server the primary server is able to create, delete, and modify VLANs. Secondary server can relay and process and save only. VTP version 3 is support Extended VLANs range (1006 – 4094). And also support Private VLANs, RSPAN VLANs, and Support MST. VTP version 3 is compatible with version 2, but not with version 1. VTP version 3 is protect against data overwrites its able to fix the configuration revision number higher updating. VTP version 3 has more secure methods for authentication of clear text or hidden password protection.