Exam 300-425 topic 1 question 80 discussion

After review all comments, I will go with C because the question does not specify a lot of info only ""new WLC is configured with the information of the other WLC" so all configs parameters including firewall open ports are in place, the only missing part is the hardware indepently of IRCM capability

A is correct. Hardware Platform can be corrected by the right software - IRCM.

A is the right one, and D is not correct , while having different mobility group names would prevent seamless roaming, it would not necessarily prevent the mobility tunnel itself from forming. The tunnels could still be established, but roaming wouldn’t work properly.

If a network consists of a mix of controller platforms, you should validate that mobility messaging actually works between them. Mobility messages cannot be exchanged at all between Catalyst 9800 and AireOS platforms unless the AireOS controllers are running release 8.8.111 or later, which introduced the Inter-Release Controller Mobility (IRCM) feature. Henry, Jerome. CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide: Designing & Implementing Cisco Enterprise Wireless Networks (Certification Guide)

I'd say the question doesn't provide enough information. The reasons for the mobility tunnel issue might be because the port is blocked, as well as the EoIP-only compatible WLC tries to establish tunnel with Secure Mobility only compatible WLC.

Enable these UDP ports for Mobility traffic: 16666 - Secured Mode 16667 - Unsecured Mode https://community.cisco.com/t5/wireless/question-about-udp-16667/td-p/1399015

The correct answer is D / the question says "information of the other WLC" but dont specife which, A is not possible because 16667 is just for secure tunnels

Explanation: The Cisco 5508 and 8510 Wireless Controllers do not support tunnel encryption protocols. They support IRCM with unencrypted mobility tunnels only. Reference: https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-10/config-guide/b_cg810/mobility_groups.html

A is correct, firewall is blocking

Looks like the answer is C The controllers have the same config so the only thing that can prevent the mobility tunnel from happening from the info we are given is that the hardware is not compatible to do tunneling. Mobility tunneling is not supported on all Cisco WLC models.

Correct answer is A The question is regarding the status of the mobility TUNNELS are still not coming up due to firewall is blocking UDP port 16667 between the WLCs.

D cannot be right because the question says "Configured the same as the other WLC",that means EVERYTHING is the same config-wise so that answer cannot be valid.My guess is different hardware types!