Exam 300-425 topic 1 question 73 discussion

A is correct. its between A and B, but A is better answer

Option A is correct, and note that option D is incorrect and misleading. This is because merely being associated with the minimum number of access points is not a suitable reason to consider a controller as the least loaded WLC. If a controller has a small number of joined access points, it might be due to the limited license capacity of that controller.

https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-mobile/71963-apload-apfall-uwn.html "The AP then attempts to join the least loaded WLC, which is the WLC with the greatest available AP capacity."

The answer is D When an AP is fully joined to a controller, the AP learns of all the controllers configured in that mobility group. Should the controllers that an AP is currently registered with go down, the AP will send discoveries to any and all controllers in the mobility group. Assuming one of the controller has the capacity to accept the AP, the AP should join the least loaded controller it can find.

Answer C Cisco APs can discover multiple contrrollers. If the joined controller becomes unavailable, the AP can simply select the next least-loaded controller and request to join it.

A? . . . it wouldn't want to pick a small WLC with low license count just because it only has a few associated, but with only a few left in the license. . . shouldn't "greatest available AP capacity" take license availability into consideration? "The AP then attempts to join the least loaded WLC, which is the WLC with the greatest available AP capacity. After an AP joins a WLC, the AP learns the IP addresses of the other WLCs in the mobility group from its joined WLC."

You can perform AP load balancing on two (or more) WLCs if you configure mobility groups properly. The LWAPP allows for dynamic redundancy and load balancing. For example, if you specify more than one IP address for option 43, an AP sends LWAPP discovery requests to each of the IP addresses that the AP receives. In the WLC LWAPP discovery response, the WLC embeds this information: Information on the current AP load, which is defined as the number of APs that are joined to the WLC at the time The AP capacity The number of wireless clients that are connected to the WLC The AP then attempts to join the least loaded WLC, which is the WLC with the greatest available AP capacity https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-mobile/71963-apload-apfall-uwn.html

If you have a firewall b/w your mobility group members, open UDP port 16666 and IP protocol 97. If you are using encrypted mobility, open UDP port 5246 and 5247. https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-5/config-guide/b_cg85/mobility_groups.html