WLC option 43

[Nub65]

Hello,

Can anyone explain to me if you need dhcp option 43 when you have your access point in the same vlan as your controllers management interface?

[marce1000]

 Yes because the AP still needs the IP adress of the controller.

 M.

[Haydn Andrews]

An AP has a number of different methods to discover the WLC:

• DHCP Option 43
• DNS entry for cisco-capwap-controller
• Management IP addresses of controllers the LAP remembers previously
• A Layer 3 broadcast on the subnet
• Statically configured information
• Controllers present in the mobility group of the WLC the AP last joined

https://www.cisco.com/c/en/us/support/docs/wireless/5500-series-wireless-controllers/119286-lap-notjoin-wlc-tshoot.html#backinfo

So if the AP and WLC are on the same layer 3 subnet then the AP can use the broadcast method to discover the WLC.

I would only recommend this method when doing lab testing. In production environments even when the WLC is on the same subnet it is best to use the DHCP option 43 or DNS methods

[Leo Laohoo]

If the APs and the WLC are in the same VLAN, DHCP Option 43 is not necessary.