Using an HA 9800 WLC to support multiple primary 9800 WLCs

[Johnny5Alive]

Is it possible to have multiple primary 9800 WLCs configured to fail over to the same shared HA 9800? 

[Haydn Andrews]

There are two ways to do HA:

SSO and N+1

SSO basically makes 2 WLCs a single cluster (think VSS) with subsecond failover

N+1 basically needs identical config and the APs configured with a secondary WLC, if the primary falls over the APs will have an outage whilst they register to the secondary WLC.

You can also combine the two of an SSO cluster and a secondary WLC (or secondary SSO Cluster)

https://www.cisco.com/c/dam/en/us/td/docs/wireless/controller/9800/17-1/deployment-guide/c9800-ha-sso-deployment-guide-rel-17-1.pdf

[Johnny5Alive]

Thank you. I am familiar with the options. What I'm not sure about is whether a single appliance can serve as a failover appliance for multiple WLCs (all within the same company) assuming they all carry the same configuration. 

[Haydn Andrews]

yes you could. Few Caverts though:

Secondary WLC

• would need to have enough capacity to manage the APs if they all failed over to them
• would need to have country codes for All primaries
• RF / Flex/ WLAN/ Policy Profiles for all sites
• RF/ Policy/ Site Tags for all sites
• Static AP tags as persistent.
• All WLCs would need to be in the mobility group
• All WLCs in the RF Group
• DCA/ TPC settings the same
• If using Webauth ensure that config the same as well including certificates loaded if applicable