Hi there,
Option 43 is one to two 'Vendor Specific DHCP Options' defined in RFC2132.
In the WLC scenario, when an Access Point broadcasts its DHCP Discover message, it uses Option 60 to specify its Vendor Class Identifier (VCI). The VCI uniquely identifies the AP platform/ model. The DHCP server in turn uses this VCI information to determine the contents of the Option 43 value. The Option 43 value will contain the IP addresses of WLCs the AP should associate with.
In summary, using these two options allows an administrator to pair Access Points with WLCs based on hardware type.
cheers,
Seb.
