Option 43 and WLC redundancy

Unanswered Question
Jan 28th, 2009

I am planning to split AP's between 2 WLC's. Also need to configure DHCP option 43, since the Management and AP-Manager interfaces will be on a different VLAN than APs.

Is Option 43 going to overwrite the primary/secondary controller configuration on AP's?

Thanks for replies.

I have this problem too.
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Scott Fella Wed, 01/28/2009 - 05:20

Option 43 provides information to a new LAP what WLC's are out on the network. As long as you have all the management ip addresses configured. The primary, secondary and or tertiary is not overwritten by option 43. When mobility is working between the WLC's and AP Fallback is enabled, then whatever you configure as primary, secondary and or tertiary will take priority over what the LAP learned from option 43.

ericgarnel Wed, 01/28/2009 - 06:45

in ISC dhcp you can do the following:

# DHCP Server Configuration file.

# see /usr/share/doc/dhcp*/dhcpd.conf.sample



ddns-update-style none;

ignore client-updates;

allow unknown-clients;

option space cisco-lwapp;

option cisco-lwapp.lwapp-controllers code 241 = array of ip-address;

option cisco-lwapp-encap code 43 = encapsulate cisco-lwapp;

#### WIFI Mgmt Subnet ######

subnet netmask {

option routers;

option subnet-mask;

option domain-name-servers,;

option domain-name "toecheese.com";

option cisco-lwapp.lwapp-controllers,,,;

default-lease-time 432000;

option log-servers;

max-lease-time 442000;

# range dynamic-bootp;

pool {


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