9800 HA Design

[zippy19]

I am new to my employer and inheriting a wireless upgrade project. We have four virtual 9800 controllers created but basically with no configuration. I did a lot back in the 5500 series but am wireless rusty and haven't done a whole lot with the 9800s. We have the following:

-   DC-1 WLC01

-   DC-1 WLC02

-   DC-1 WLC03

-   DC-2 WLC01

The plan is to make DC-1 WLC01 and DC-1 WLC02 a HA pair. Can you do three chassis' in this design and have DC-2 WLC01 be in there too (so that way it is hot/active and one management plane), or do you have to configure this independently and set DC-2 WLC01 as the secondary WLC on each controller?

DC-1 WLC03 is slated to be a guest anchor. Does this need to be its own standalone box or can this function be merged with the others?

Thank you in advance!

[marce1000]

 - A few short basics HA SSO (stateful HA) can only consist of 2 nodes.
    You can consider N+1 high availability for add ons (nodes) to such a deployment if desired
    Checkout : https://www.cisco.com/c/dam/en/us/td/docs/wireless/controller/9800/17-4/deployment-guide/c9800-n-plus-1-high-availability-wp.pdf

      Guest anchor remains a standalone controller : https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/213912-configure-mobility-anchor-on-catalyst-98.html

    Useful document for initial configurations : https://www.ciscolive.com/c/dam/r/ciscolive/global-event/docs/2024/pdf/BRKEWN-2094.pdf

   ++ Last but certainly not least : always checkout the configuration of a 9800 controller 
                                                      using the CLI command show tech wireless and feed the output from
                                                      that into    Wireless Config Analyzer

   A must do!!

[Leo Laohoo]

Is this wireless network "highly critical", i.  e.  24x7?

Can this wireless network afford, say, reboot of the controllers every 4 months?

[Scott Fella]

You are going to get various different answers on what folks would do.  Im not a fan of SSO and prefer N+1,  I would have all three in an N+1 and use the other controller as a guest anchor if that is what you plan on doing.  What you have to think about is, why would you anchor guest from one DC to another.  If you have internet egress at each DC, then don't even bother with a guest anchor.  As you can see here, there are a lot of questions that would need to be answered in order to really provide you with something of a design that hopefully you and your team can support in the future.