A P P E N D I X A Configuring Dhcp Option 43 For Cisco 520 Series Access Points - Cisco 521G - Unified IP Phone VoIP Configuration Manual

Configuring Option 43 for Cisco 520 Series Access Points
Configuring Option 43 for Cisco 520 Series Access Points
To configure DHCP Option 43 for Cisco 520 series access points in the embedded Cisco IOS DHCP
server, follow these steps:
Enter configuration mode at the Cisco IOS CLI.
Step 1
Create the DHCP pool, including the necessary parameters such as default router and name server. A
Step 2
DHCP scope example is as follows:
ip dhcp pool <pool name>
network <IP Network> <Netmask>
default-router <Default router>
dns-server <DNS Server>
Where:
Add the option 60 line using the following syntax:
Step 3
option 60 ascii " VCI string "
For the VCI string, use the value from
Step 4 Add the option 43 line using the following syntax:
option 43 hex < hex string >
The hex string is assembled by concatenating the TLV values shown below:
Type is always f1(hex). Length is the number of controller management IP addresses times 4 in hex. Value
is the IP address of the controller listed sequentially in hex.
For example, suppose that there are two controllers with GUI IP addresses 10.126.126.2 and
10.127.127.2. The type is f1(hex). The length is 2 * 4 = 8 = 08 (hex). The IP addresses translate to
0a7e7e02 and 0a7f7f02. Assembling the string then yields f1080a7e7e020a7f7f02. The resulting Cisco
IOS command added to the DHCP scope is listed below:
option 43 hex f1080a7e7e020a7f7f02
Cisco 500 Series Wireless Express Mobility Controller Configuration Guide
A-2
<pool name> is the name of the DHCP pool, such as LAP521
<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
<Default router> is the IP address of the default router, such as 10.0.0.1
<DNS Server> is the IP address of the DNS server, such as 10.0.10.2
Type + Length + Value
Appendix A Configuring DHCP Option 43 for Cisco 520 Series Access Points
Table A-1. The quotation marks must be included.
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