VTP mode from Client to Transparent

[Andrew Cormier]

   Hi,

Having an issue with Catalyst 3560G and 3750 switches and VTP.

We have a 3750 switch that is in server mode. We dont actually use VTP but never changed it from server mode and never had any issues.

Into that 3750 we have a number of 3560 switches. The 3560s are on different locations and are edge switches. The users plug directly into them.

All the 3560 switches are in TRANSPARENT mode except for one. It is in CLIENT mode.

VLAN 10 exists on all the switches.

Devices that are on VLAN 10 can reach each other no problem.

The 3560 switch in CLIENT mode has a server on VLAN 10. Also reachable UNTIL.

I run VTP mode transparent and I can STILL reach the server but have a number of very odd network issues (call routing with VOIP)

I know this is related because the second I do VTP mode client again the issue is resolved.

So I tried this...  from the switch in client mode I run

VTP mode transparent

no vlan 10 (delete the vlan)

vlan 10

name vlan_10 (to recreate the vlan)

At that point I have no connectivity to the server on that switch (even though I recreated the VLAN)

Not sure what I am doing wrong. Do I have to delete and recreate on the core 3750 as well?

All the other switches have interconnectivity on that vlan.. only the one that is in client mode fails when I go to transparent mode.

[Elton Babcock · Accepted solution]

When you change into transparent mode your VLANs should all remain but will just be local to the switch. You should see them all appear in the running config after changing. I believe the issue might be when you delete the VLAN the physical port goes into a state I can't remember the name of off the top of my head. You might need to bounce the port at this point to get it out of that state.

Sent from Cisco Technical Support iPhone App

[Andrew Cormier]

Thanks Elton!

It might be a little more complicated than I thought

Until I could get the issue resolved I plugged the server into another 3560 that was already in transparent mode.

Doing this seemed to work fine (why wouldnt it, there were no issues with the second switch). Did it at night, did my tests, all good.. going home.

The next morning I come in and see that there is the same problem on the second switch (voip calls internally work but external calls doing have voice going out).

So anyway, we have a bank of hours with Cisco experts and I will get them to look at it BUT.. one question.

When you say bounce the port do you mean shut int gi0/22 (for example)?

[Elton Babcock]

That is correct. Bouncing the port means just shutting it down and then doing a no shut on the port.

You can also do a "show interface status" and see if the port is anything other than "connected" prior to bouncing the port.