350-401 Question 171
Select 3An IT administrator is deploying new access points (APs) in an enterprise network. The APs must discover and join a wireless LAN controller (WLC). Which of the following methods can the APs use to discover a WLC?
- A
Broadcasting a discovery request on the local subnet
- B
Using DHCP option 43 to obtain the WLC IP address
- C
Querying a DNS server for a pre-configured WLC name
- D
Manually configuring the WLC IP address on the AP
- E
Relying on Layer 3 routing protocols to forward discovery packets
Show answer and explanation
Correct answers: B, C, D
Explanation
Access points can use multiple methods to discover and join a wireless LAN controller (WLC). DHCP option 43 and DNS are automated methods often used in scalable deployments, while manual configuration is a fallback or for specific cases. Broadcasting in the local subnet is not a valid method, and routing protocols are not involved in the discovery process. Understanding these mechanisms is crucial for effectively deploying and troubleshooting enterprise wireless networks.
- A. Incorrect.
Broadcasting a discovery request is not used in WLC discovery because it does not scale efficiently across subnets. APs typically use other mechanisms for discovery.
- B. Correct.
DHCP option 43 is a common method for APs to discover the WLC IP address during the boot process. This option allows the DHCP server to provide the WLC IP address to the AP.
- C. Correct.
APs can query a DNS server for a pre-configured WLC name, such as 'cisco-capwap-controller.localdomain.' This is another valid method for discovering a WLC.
- D. Correct.
Manually configuring the WLC IP address on the AP is a valid method, though it requires manual intervention and is typically used as a fallback or in small networks.
- E. Incorrect.
Layer 3 routing protocols are not used for WLC discovery. Instead, the CAPWAP protocol is used for communication between APs and WLCs.