Exam 300-425 topic 1 question 107 discussion

D, according to this document: https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-1/HA_SSO_DG/High_Availability_DG.html#pgfId-43357

At first glance, you might think that option D is correct, and it may even seem logical. Since if SSO is disabled, then obviously, the SSO functionality won’t work... However, pay attention to the question! It is asking what causes the secondary controller to go into maintenance mode. This happens when the redundancy port encounters an issue. I believe the diagram provided in the question is meant to be misleading.

Management & Redundancy-management should be on same subnet. Each unit need to have unique redundancy-management IP address & management IP address is shared between units.

C - Alonzo: My reason we wrong but the answer is "C" as you pointed out.

The answer is C Maintenance Mode: There are few scenarios where the Standby WLC may go into Maintenance Mode and not be able to communicate with the network and peer: -Non reachability to Gateway via Redundant Management Interface -WLC with HA SKU which had never discovered peer ***Redundant Port is down*** -Software version mismatch (WLC which boots up first goes into active mode and the other WLC in Maintenance Mode)

C - 169.254.x.x indicates no DHCP or static assignment was given. The engineer needs to configure that.

C, look at the comment from mohanak here: https://community.cisco.com/t5/wireless/wlc-ha-maintenance-mode/td-p/2927232 There are few scenarios where the Standby WLC may go into Maintenance Mode and not be able to communicate with the network and peer: - Non reachability to Gateway via Redundant Management Interface - WLC with HA SKU which had never discovered peer - Redundant Port is down - Software version mismatch (WLC which boots up first goes into active mode and the other WLC in Maintenance Mode) A / not correct, RP is l2 port where RMI is l3 B/ not correct keepalives doesnt matter and wont cause hotstandby to go to maintenance mode C/ correct, if RP is down that indeed causes standby to go to maintenance mode D/ incorrect, according to the phrasing of the question, engineer is just preparing the confgiuration. enabling SSO is the final step after all the rest of config is finished. Once enabled WLCs will reboot and discover the HA SSO neighbors and join the HA SSO stack. C/

The right answer is C. According to this URL: https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-1/HA_SSO_DG/High_Availability_DG.html#pgfId-105076 -The Standby WLC sends Keepalive to the Active WLC and expects and acknowledgment within 100 msec as per the default timer. This can be configured in range from 100-400 msec - So B is not correct 2. SSO must be enabled ir order to pair both controllers so D is not correct 3. Once SSO is enabled, it will reboot the WLCs. While it boots, the WLCs negotiate the HA role as per the configuration via Redundant Port. If the WLCs cannot reach each other via Redundant Port or via the Redundant Management Interface, the WLC configured as Secondary may go in to Maintenance Mode. So the correct answer is C

The question states "An engineer is designing SSO on pair of controllers". Why would you disable SSO when you are trying to build a SSO connection? I think it is C

Answer: C

C - ‘There are few scenarios where the Standby WLC may go into Maintenance Mode and not be able to communicate with the network and peer: • Non reachability to Gateway via Redundant Management Interface • WLC with HA SKU which had never discovered peer • Redundant Port is down • Software version mismatch (WLC which boots up first goes into active mode and the other WLC in Maintenance Mode)’ High Availability (SSO) Deployment Guide - Cisco

D is correct