12 Configuring DHCP Option 43 and DHCP Option 60
This section contains a DHCP Option 43 configuration example on a Windows 2003 Enterprise DHCP
server for use with Cisco Aironet lightweight access points. For other DHCP server implementations,
consult product documentation for configuring DHCP Option 43. In Option 43, you should use the
IP address of the controller management interface.
Note DHCP Option 43 is limited to one access point type per DHCP pool. You must configure a
separate DHCP pool for each access point type.
The 2700 series access point uses the type-length-value (TLV) format for DHCP Option 43. DHCP
servers must be programmed to return the option based on the access point’s DHCP Vendor Class
Identifier (VCI) string (DHCP Option 60). The VCI string for the 2700 series access point is:
Cisco AP c2700
Note If your access point was ordered with the Service Provider Option (AIR-OPT60-DHCP)
selected in the ordering tool, the VCI string for the access point contains ServiceProvider. For
example, a 2700 with this option will return this VCI string:
Cisco AP c2700-ServiceProvider
The format of the TLV block is listed below:
•Type: 0xf1 (decimal 241)
•Length: Number of controller IP addresses * 4
•Value: List of WLC management interfaces
To configure DHCP Option 43 in the embedded Cisco IOS DHCP server, follow these steps:
Step1 Enter configuration mode at the Cisco IOS CLI.
Step2 Create the DHCP pool, including the necessary parameters such as default router and name
server. A DHCP scope example is as follows:
ip dhcp pool <pool name>
network <IP Network> <Netmask>
default-router <Default router>
dns-server <DNS Server>
Where:
<pool name> is the name of the DHCP pool, such as AP2702
<IP Network> is the network IP address where the controller resides, such as
10.0.15.1
<Netmask> is the subnet mask, such as 255.255.255.0