Solved: Re: WLC HA pairing issue

david.fletchall · ‎03-07-2022

I have an existing 3504 WLC that I would like to have in an HA pair with another 3504 WLC.

WLC1 has the following software; (this is the existing, in service Primary)

Product Name..................................... Cisco Controller
Product Version.................................. 8.5.131.0
RTOS Version..................................... 8.5.131.0
Bootloader Version............................... 8.5.103.0
Emergency Image Version.......................... 8.5.103.0

WLC2 has the following software; (this is the secondary)

Product Name..................................... Cisco Controller
Product Version.................................. 8.9.111.0
RTOS Version..................................... 8.9.111.0
Bootloader Version............................... 8.5.103.0
Emergency Image Version.......................... 8.5.103.0

I'm assuming this will cause possible issues if I try to pair them. I'd rather not upgrade WLC1 since its 24x7 in production but I dont want to proceed with the task to configure HA and activate SSO if this mismatch is going to blow things up.

Can I get some advise on best practice to handle this situation? Thanks.

Scott Fella · ‎03-07-2022

There are two different methods for high availability. One is N+1 in which you configure both controllers alike and the other is SSO, in which they will sync. Now, my suggestion is for you do downgrade the new 3504 to the same code you are running on the existing. Then setup N+1, which will not impact anything. You never want to have different code versions for one, even in N+1 design. For SSO, it's a requirement to have the same model and code.

If you need to know more about N+1, take a look here:

PowerPoint Presentation (ciscolive.com)

For SSO, which will require downtime, take a look here:

High Availability (SSO) Deployment Guide - Cisco

-Scott
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