VLAN Trunk Protocol Question

[dskalish19004]

Good afternoon

I am in the process of upgrading my 2950s to updated 2960s. But I need to keep what I have in place a little longer before I deploy the new switches

I have 9 of these switches on a metro fiber network across my sites. One is a command cluster switch, acting as a "VTP server" mode, the rest in client mode using a handful of vlans across sites

One of my switches stopped inheriting new vlan information as created on the command switch. Other switches respond normally with new Vlan info.

However existing vlan configurations are normal on this affected switch, traffic passing normally

The only difference I can tell at this point, is most switches are on VTP Version 2, Configuration revision 166, however I noticed this switch not inheriting the new information, is VTP version 2, revision 144

This is not my area of expertise, so any guidance is appreciated. I checked to see the trunk port is indeed active, allowing "ALL" . These switches are part of a Domain as set with a VTP password.

Thank you

[Paul Chapman]

Hi -

Since your "broken" switch is on a lower revision number, the easiest way to fix it would be to convert it from client mode to transparent.  Then re-verify the VTP domain name and password (both are case sensitive).  Then convert the switch back to client mode.  You should see the switch download the new database and the revision number will match all other switches.

I recommend doing this during an outage window in case the VLANs on the "broken" switch are accidentally removed or (more likely) a STP reconvergence event occurs.

PSC

[dskalish19004]

Thank you also for your great suggestion. I just tried this. upon doing so, the vlan information remains as it is after switching from Client to Transparent. and then back to client. (After Apply and OK after each change, then save config, in Cisco Network Assistant software)

The difference this time, is that on the "configure VTP tab, the settings are showing VTP Version 2, and the Configuration version is 0 (zero), whereas it was 144 before.

The other switches in the network are reading configuration version as 166

[Paul Chapman]

Hi -

Yes. When you convert from client to transparent all the VLANs remain in place.  When the switch joins the VTP domain, the highest version of the database is replicated to all clients.

PSC

[paul driver]

Hello

What vtp mode is this switch in?
It needs to be in client or server mode to accept summary advertisements, If its transparent mode then change it client mode, this will reset the revision number on that switch and it should then automatically update itself with the new vtp information.

Another way if applicable, Would to delete the vlan.dat file from flash and reboot the switch

Note: if your vtp client/transparent switch has vlans that your vtp server doesn't have then these vlans will be deleted from the vtp client/transparent switch when it update correctly because the vtp server will overwrite the switch vtp database.

res
Paul

[dskalish19004]

Thanks for your reply. This is a switch in client mode. Given your tip and from others, I may take another switch and configure it in such a way that it makes for a fallback, in the event I get myself caught in error.