VTP ver.2

[milan.kulik]

Hello,

has anybody tried to enable VTP ver 2 mode?

When I try to enable it on my Cat 2924XL running IOS 12.0(5)WC5a I receive "VLAN 1003 ring number missing" and "VLAN 1005 bridge number missing" error messages.

I have read somewhere that to move from ver 1 to ver 2 it is enough just enable v2 mode on one VTP server and the rest of my network will change automatically. Is this correct? If yes, are there some trunk outages during the change process?

Regards,

Milan

[Prashanth Krishnappa]

VTP Version 2 (V2) is not much different than VTP Version 1 (V1). The major difference is that VTP V2 introduces the support for Token Ring VLANs. If you are using Token Ring VLANs, you need to enable VTP V2. Otherwise, there is no reason to use VTP V2.

http://www.cisco.com/warp/public/473/21.html#vtp_v2

[DWAM_2]

Hello !

The difference between v1 and v2 are here :

http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_guide_chapter09186a008007f332.html#xtocid5

I think your are true to say that you have just to enable v2 mode on one VTP server and the rest of you network will change automatically.

After it's the same that prkrishn =)

[milan.kulik]

Hi,

I'm interested in following feature:

Version-Dependent Transparent Mode—In VTP version 1, a VTP transparent switch inspects VTP messages for the domain name and version and forwards a message only if the version and domain name match. Since only one domain is supported in the supervisor engine software, VTP version 2 forwards VTP messages in transparent mode, without checking the version.

This description is not clear to me:

Does the V2 transparent mode switch check the domain name or not?

And a general question:

Is the domain name match necessary for trunk to work?

I.e., when I'm having two switches each in a different VTP domain do I have to configure trunk nonegotiate? Or is it possible to use trunk negotiaition (i.e. VTP is not involved in trunk negotiation, there is just DTP used)?

Regards,

Milan

[DWAM_2]

Hello

When you configure a switch as VTP transparent, you must configure VLAN information manually on the switch. A VTP-transparent switch does not advertise VLAN information to other switches and will ignore VTP updates from VTP clients and servers.

http://www.cisco.com/en/US/products/hw/switches/ps700/products_command_reference_chapter09186a00800eb73f.html#3315

VTP is used to propage Vlans around the network with the same domain name.

If you have two switch each in different vtp domain, the propagation of vlan will not function. But i think that the trunk can work if you have declared the same id vlan on each switch.

The best is to try on your spare network.

Regards.

[milan.kulik]

Well,

I've done some lab tests and the results are:

VTP transparent switch DOES forward VTP updates. But there is a difference between VTP v1 and v2: In VTP v1 the domain name must match with the domain name configured on the transparent switch. VTP v2 transparent switch doesn't check the domain name.

Regarding the trunk:

If you configure nonegotiation on the trunk it works OK even while switches involved are in different VTP domains. It is also possible to have different VLAN sets on both trunk sides. If the switch receives a frame which is tagged for VLAN is doesn't know the frame is just discarded and no error message goes to syslog. You can detect this VLAN set misconfiguration via Logical Discrepancy Report in CiscoWorks.

I'm not sure if trunk works this way while trunk negotiation is enabled - I don't have two Cat4000 in my lab. But I suppose yes.

Regards,

Milan

[DWAM_2]

Thanks for your feedback,

but i need i little precision about your first test.

When you are in VTP v1 and when the vtp name transparent doesn't match the vtp domain name, what's happen ?

Network down ? Packet dropped? Packet not forward and that's all ?

Best Regards.

[milan.kulik]

AFAIK, packet not forwarded and that's all.

Regards,

Milan