Which action resolves the issue?

An engineer has deployed a single Cisco 5520 WLC with a management IP address of 172.16.50.5/24. The engineer must register 50 new Cisco AIR-CAP2802I-E-K9 access points to the WLC using DHCP option 43. The access points are connected to a switch in VLAN 100 that uses the 172.16.100.0/24 subnet.

The engineer has configured the DHCP scope on the switch as follows:

Network 172.16.100.0 255.255.255.0

Default Router 172.16.100.1

Option 43 ASCII 172.16.50.5

The access points are failing to join the wireless LAN controller.

Which action resolves the issue?
A . configure option 43 Hex F104.AC10.3205
B. configure option 43 Hex F104.CA10.3205
C. configure dns-server 172.16.50.5
D. configure dns-server 172.16.100.1

View Answer

Answer: A

Explanation:

The Option 43 hexadecimal string is assembled as a sequence of the TLV values for the Option 43 suboption: Type + Length + Value. Type is always the suboption code 0xf1. 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.

On this question, there is 1 controller with management interface IP addresses 172.16.50.5/24. The type is 0xf1. The length is 1 * 4 = 8 = 0x04. The mgmt IP addresses 172.16.50.5 translate to ac.10.32.05 (0xac103205). When the string is assembled, it yields f108c0a80a05c0a80a14. The Cisco IOS command that is added to the DHCP scope is: option 43 hex f104ac103205