I need to move a number of switches from VTP client to transparent in an attempt to gain control of my STP domain as the aim is to delete vlans from the switches that are not required.
As I change the first switch to transparent (without deleting any vlans) I loose connectivity to a number of IP phones despite the voice vlan still being listed in the switch running config and 'show vlan'. My phone is connected to the switch in question and although it was not saying 'configuring IP' like the others I could only get intermittent ping responses from the IP.
As soon as the switch is changed back to a VTP client device everything returns to normal.
Any ideas would be much appreciated?
had a similar issue before. VTP Pruning turned out to be the culprit. Turning it off on the VTP Server solved my problem.
Somehow, correct me if I'm wrong, the Voice VLAN gets pruned the moment SW2 is changes to transparent mode. SW2 disappears from the VTP Domain, and SW1 (I assume since it isnt getting VTP Messages from SW2) Prunes the VLANs SW2. This is regardless of the VLANs allowed over the trunk and VLANS statically configured on SW2.
This means that traffic to this vlan does not get sent over the trunk to that switch, resulting in your voice VLAN losing connection.