VTP Version 3
An aide-memoir, cum cliff-notes:
VTP version 3 differs from earlier VTP versions in that it does not directly handle VLANs. VTP version 3 is a protocol that is only responsible for distributing a list of opaque databases (somewhat like like LDAP!) over an administrative domain. When enabled, VTP version 3 provides these enhancements to previous VTP versions:
•
Support for extended VLANs.
•Support for the creation and advertising of private VLANs. (NICE!!)
•Support for VLAN instances and MST mapping propagation instances. (good – I like MST very much)
•Improved server authentication. (MD5)
•Protection from the “wrong” database accidentally being inserted into a VTP domain. (a major shortcoming of previous versions)
•Interaction with VTP version 1 and VTP version 2. (as one would hope / expect)
•Ability to be configured on a per-port basis. ( I guess this helps the previously mention backward-compatability with V1 and 2). I’d like to test this – just to see it in action and do some debugging / packet sniffing. When I do, I’ll post a wireshark capture on this blog.
Limitations of Version 3:
The limitations of VTP version 3 are as follows:
•Two VTP version 3 regions can communicate only over a VTP version 1 and VTP version 2 region in transparent mode.
•Leaving a server in a VTP version 2 region so that it will receive its VTP information from a VTP version 3 region could cause a problem. If a configuration change occurs in the VTP version 1 and VTP version 2 region, the revision of the database may become higher than the one that is generated by the VTP version 3 region, and the updates from the VTP version 3 region may be ignored.
