2 questions, actually:
I've got a 2960 switch running IOS 12.2(25). It has an access point connected to it but guests were unable to connect to one of the wireless networks the AP provides.
One of my techs looked into it and said that VLAN 12 was not configured on the switch; VLAN 12 is the VLAN the guest wireless network uses. He just did "vlan 12" at a conf t prompt and it all woke up. He didn't add any interfaces to VLAN 12. So question 1 is this: VLAN 12 exists on the AP, and the switch port the AP is on is configured to trunk. Why was it necessary to create VLAN 12 on the switch? None of the resources accessed by users of the guest wifi are on that switch, they just need to use its backbone to our internet router, which is also configured to trunk.
Now I can see VLAN 12 in there when I do a "sho vlan", but I can't see the command that creates VLAN 12 in the running config. So question 2 is, when the switch reboots or whatever, how does it know to re-create VLAN 12? Is the info stored somewhere other than the running-config?
Asking because I can envision a time when the switch dies and we go to swap in a replacement by throwing a copy of the old config on it, then sit around scratching our heads because "everything should be identical" when really the VLAN is not being created.