Core Issue
The concept of voice or auxiliary VLAN does not directly apply and can cause problems because the Cisco 7935 IP Conference Phone has no 10/100 port to connect a PC to other similar Cisco 7900 Series IP Phones.
Resolution
To resolve this issue, remove references to voice VLAN or auxiliary VLAN from the port on the switch that the Cisco 7935 connects to and put that port in the VLAN whose number corresponds with the voice VLAN.
This is the configuration for Cisco IOS Software products:
configure terminal
interface 0/x
switchport access vlan z
no switchport voice vlan z
no switchport mode trunk
no switchport trunk encapsulation dot1q
end
This is the configuration for Catalyst Operating System (OS) products:
set port auxiliaryvlan x/y none
set vlan z x/y
set trunk x/y off
For more information about resolving Skinny registration issues, refer to these documents: