Cisco Catalyst 9800 WLC(Hardware) & Catalyst 9800-CL

[aungyekhant]

We want to by a wireless hardware controller(C9800-L) for our Access Point Management as a primary controller.

We also need a backup WLC. Therefore, we want to deploy Cisco WLCv 9800-CL on our Esxi. (NOTE: this will cause our budget)

is it ok to deploy 2 WLC in same broadcast domain?

Can backup WLC take the primary role when the primary hardware controller is down?

is there any risk in our plan?
is my plan is good or not? please suggest another plan did you have.

Really thanks for your reply and support.

Best Regards
Aung Ye

[balaji.bandi]

Sure you can deploy 1 Physical and one Virtual, and they can be in VLAN.

Make sure you understand the failover  between Physical and Virtiual (last time i was test, from AP Physical to WLC taking 3min fail over timings.) but vWLC in DC (may be that is the reason).

[aungyekhant]

fail over timings is ok for us. thanks for your kindly answer me.

[Arshad Safrulla]

You can have HA, no doubt. But it won't be HA SSO, you wouldn't get stateful switchover from one WLC to other.

HA mode which will work in your setup would be N+1, in this case to minimize the downtime you need to do lot of things manually. Like maintaining software same across both WLCs, maintaining the configuration across both WLC's, RF grouping and RRM related stuff. Priming the APs for primary and secondary controllers etc. Most importantly you have to make sure that proper dedicated compute and storage resources are assigned to the 9800-CL and hyper threading is disabled for the compute node where the 9800-CL VM lives.

When there is a failover provided that both WLCs and APs configured correctly downtime will be like 30 seconds to 2 minutes. It may increase or decrease depending on multiple factors.  

I would suggest convincing your management to purchase another 9800-L and building HA SSO as this will bring significant enhancements to failover time and also minimize the human error factor on the failure.

[aungyekhant]

Thanks for your suggestions.

[marce1000]

 - I would prefer full HA SSO , but then the controllers need to be of the same model. May need somewhat more investment, but more ease of management, because managing a separate controller takes time too (software maintaining , having sufficient resources,...)

 M.