350-401 Question 170
Select 3A network engineer has deployed a new lightweight access point (AP) in a branch office. The AP needs to discover and join a Wireless LAN Controller (WLC) in the network. Which of the following methods can the AP use to discover the WLC during the discovery phase?
- A
Broadcasting a CAPWAP discovery request on the local subnet
- B
Using DNS to resolve the controller's domain name
- C
Using an IP address obtained via DHCP Option 43
- D
Manually entering the WLC IP address on the AP's configuration interface
- E
Using Layer 2 broadcast frames to locate the WLC
Show answer and explanation
Correct answers: A, B, C
Explanation
When a lightweight access point is powered on, it must discover a WLC to join and operate. Common discovery methods include broadcasting CAPWAP discovery requests on the local subnet, using DNS to resolve the WLC's domain name, and obtaining the WLC's IP address via DHCP Option 43. These methods enable the AP to find a WLC efficiently within the network. Manual configuration and Layer 2 broadcasts are not valid discovery methods for lightweight APs.
- A. Correct.
Correct. The AP can use broadcast CAPWAP discovery requests on the local subnet to locate a WLC if it is in the same Layer 2 domain.
- B. Correct.
Correct. The AP can use DNS to resolve a preconfigured domain name (e.g., cisco-capwap-controller.localdomain) to discover the WLC.
- C. Correct.
Correct. DHCP Option 43 can provide the AP with the IP address of the WLC during the discovery process.
- D. Incorrect.
Incorrect. Lightweight APs do not support manual configuration of the WLC IP address via their interface; they rely on automated discovery methods.
- E. Incorrect.
Incorrect. Lightweight APs use CAPWAP (Control and Provisioning of Wireless Access Points) for discovery, which operates at Layer 3. Layer 2 broadcast frames are not used for this purpose.