There are three versions of VTP in Cisco Switches. VTP Version 3 is very new and will be available only in the latest IOS versions. Remember that all VTP is off by default. If you want to use VTP in your network, you must decide whether to use version 1 or version 2 or version 3. When you enable VTP on Switches, by default VTP operates in version 1 only.
VTP version configuration on Cisco Switch
You can configure VTP version using VTP version command on Cisco Switches.
Cisco_Switch(config)#vtp version ?
<1-2> Set the adminstrative domain VTP version number
Difference between VTP Version 1 and Version 2
VTP Version 2 supports additional features compared to VTP version 1. Version 1 is adequate for most systems that do not contain Token Ring feature. Many of the Version 2 features impose tighter management control on VTP, which could very well help avoid problems if you are merging VTP systems.
Support/Processing in Version 2
|Token Ring||VTP version 2 supports Token Ring Bridge Relay Function (TrBRF) and Token Ring Concentrator Relay Function (TrCRF) VLANs.|
|Unrecognized Type-Length-Value (TLV)||In Version 2, a server or client will propagate TLVs even those it does not understand. It also saves them in NVRAM when the switch is in VTP server mode. This could be useful if not all devices are at the same version or release level.|
|Version-Dependent Transparent Mode||Version 2 supports multiple domains while Version 1 supports only 1. Normal behaviour for Version 1 would be to forward messages only if they match the destination domain name and version. VTP version 2 does not do this check before forwarding.|
|Consistency Checks||VTP version 1 does more consistency checking on messages, which can add overhead. As long as the MD5 digest on a message is correct, VTP version 2 will forward it. In VTP version 2, VLAN consistency checks (such as VLAN names and values) are performed only when you enter new information through the CLI, the Cluster Management Software (CMS), or SNMP.|
VTP version 3 introduces more features compared to Version 1 and Version 2, I will cover Version 3 features in next post.
Filed Under: VLAN/VTP
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