To understand the difference between both the version let’s first quickly see what is VTP and it’s function. VTP stands for VLAN Trunking Protocol. It is cisco proprietary protocol which provides a means by which cisco switches can exchange VLAN configuration details. VTP advertises each existing VLAN in the network based on its VLAN ID and name. It has several benefits but also might become a problem if not configured properly.
The main difference between VTP Version 3 and VTP Version 2 is that the version 3 supports extended range VLANs. Thus, supporting up to 4k VLANs. It also supports for the creation and advertisement of private VLANs. VTP version 3 provides protection against an unnecessary overwriting of the VLAN database by a switch with a greater revision number. It can also synchronize MSTP region configuration details throughout the VTP domain. Also, the VTP password can be only encrypted for VTPv3 by entering the command vtp password password hidden in the global configuration mode. After entering this command, the password would be stored in an encrypted format in the vlan.dat file and even the show vtp password command will be unable to reveal the original password.
VTP v2 is almost similar to VTP v1. The only major difference is that VTP V2 supports for Token Ring VLANs. If using Token Ring VLANs, you should enable VTP V2. Or else, there is no reason for using VTP V2. VTP v2 stores the password as ASCII in a running configuration whereas version 3 stores it as a hexadecimal number which enhances the server authentication process.
With VTP version 2, if a switch is set to transparent mode, it will communicate without checking version information. Whereas with VTP version 1, it will check the domain and version before if forwarding any frame.
VTP version 3 introduced the concept of transferring an opaque database in situations where VTP version 2 interacted with the VLAN process directly. Also, by providing a reliable and efficient transport process for a database, usability can be expanded in terms of supporting different VLAN environment. For this to happen, VTP version 3 provides support for the MST mapping table.
VTP version adds a number of enhancements to VTP version 1 and VTP version 2 such as it supports a structured and secure VLAN environment; feature enhancement beyond support for a single database or VTP instance; protection from unwanted database overrides during insertion of the new switches; provides option for clear text or hidden password protection; configuration option on a per port basis instead of only a global scheme; improved resource handling and much efficient transfer of information; support for VLAN instances and MST mapping propagation instances.
For advanced Certification Training