9800 deployment in multiple sites

[komiks]

In deploying 9800 to multiple sites (3 or more) is there an option to deploy in HA setup? I saw SSO but it only requires 2 devices. 

or is there a way to configure the 9800 in 3 standalone setup but users can seamlessly connect to wireless as if registering to one?

[Mark Elsen · Accepted solution]

  - HA SSO targets local failover and can consist of a pair only , indeed.  For multiple controllers (or sites) you can use N+1 high availability where the APs need to fallback manually to another controller if needed ,

 M.

[komiks]

in n + 1 for example 3 controllers, 2 wlc is active and the other 1 is in standby?

[Mark Elsen]

           >...in n + 1 for example 3 controllers, 2 wlc is active and the other 1 is in standby?
  No ,  in n+1 all controllers 'are available' ; in the AP configuration (high availability part) a number of controllers is
  specified , (primary - secondary,..._) to choose from in the specified order , 

 M.

[balaji.bandi · Accepted solution]

How is these sites connected ? do you have Layer 2 extention, then its easy, if not you have only option N+1

again depends on deployment type Local switching or Central switching, so consider high bandwidth depends on clients base and deployment size.

You can look n+1 controller option here :

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

Note : do the testing failover times when you deploying N+1 (as per my experience when i we are testing, had 2min failover from one WLC to WLC) - may be latest code may have fixed now)

[komiks]

if there is a L2 connectivity, is there other option aside from n + 1?

[Mark Elsen]

             >...if there is a L2 connectivity, is there other option aside from n + 1?
  - You can only choose between HA-SSO ('strong high availability' - used on the local intranet )
      or n+1 for high availability scenario's ; usually you won't have L2 only
     between remote sites. (Note that a local HA-SSO pair can be part of an n+1 scenario for high availability between controllers and
     sites)

 M.

[Rich R · Accepted solution]

HA-SSO should generally only be used for a pair of co-located WLCs.
The WLCs require high bandwidth and low latency connections for SSO redundancy so it is generally not recommended between sites unless the sites are close enough with high bandwidth layer 2 connections to satisfy the SSO requirement.

Also remember that in SSO only 1 WLC is active so the APs in the standby site would have to use a remote site which was active.  That also would not work well for 3 sites but you could have Site A + Site B (HA-SSO which looks like a single controller to the APs) + Site C (N+1 HA operating as secondary WLC for the APs).  I do not recommend this arrangement.

For 3 remote sites I'd say it's best to work with them as N+1.  The APs at each site have the local WLC as primary with the other 2 WLCs as secondary and tertiary (configure on AP HA tab).  You will need to make sure all WLCs have the config for all the APs kept in sync and ensure that the APs have the required connectivity to reach all the WLCs and the connectivity for the WLANs if they are centrally switched.  You'll also want to configure mobility between the WLCs too.