Wireless LAN Controller Discovery Methods
Question
Which two methods are used by an AP that is trying to discover a wireless LAN controller? (Choose two.)
Answers
Explanations
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A. B. C. D. E.CD.
https://www.cisco.com/c/en/us/support/docs/wireless/5500-series-wireless-controllers/119286-lap-notjoin-wlc-tshoot.html#backinfoSure, I'd be happy to help!
When an access point (AP) is trying to discover a wireless LAN controller (WLC), it can use different methods to find and connect to the controller. The two methods that are commonly used by APs for WLC discovery are:
A. Cisco Discovery Protocol (CDP) neighbor: This method involves using CDP, a proprietary protocol developed by Cisco, to discover and connect to a WLC that is directly connected to the same network segment as the AP. When an AP is connected to a switch that has a WLC attached to it, the AP can use CDP to discover the WLC and establish a connection.
B. Querying other APs: This method involves using the APs that are already connected to the WLC as a source of information about the controller's location. When an AP is unable to discover a WLC using other methods, it can send out queries to other APs that are already connected to the same network. These queries ask for information about the WLC, including its IP address, and the APs can respond with the necessary details.
The other options given in the answer choices are:
C. DHCP Option 43: This method involves using DHCP to provide the AP with the IP address of the WLC. The WLC's IP address is encoded in a specific format and sent to the AP in the DHCP Option 43 field. When the AP receives the IP address, it can use it to establish a connection to the WLC.
D. Broadcasting on the local subnet: This method involves the AP broadcasting a message on the local subnet to discover the WLC. The message can be a simple broadcast or a directed broadcast to a specific IP address range. When the WLC receives the message, it can respond to the AP with the necessary information.
E. DNS lookup CISCO-DNA-PRIMARY.localdomain: This method involves using DNS to resolve the name of the WLC to its IP address. The AP sends a DNS query for the name "CISCO-DNA-PRIMARY.localdomain" and receives the IP address of the WLC as a response. The AP can then use the IP address to establish a connection to the WLC.
In summary, the two methods used by an AP to discover a WLC are CDP neighbor and querying other APs. DHCP Option 43, broadcasting on the local subnet, and DNS lookup are also possible methods, but they are not the most common.
