What is HA SSO and N+1 ,N+N redunancy in controller

[knaik99]

What is HA SSO and N+1 ,N+N redunancy in controller?

what is redundancy type in WLC

[Rasika Nayanajith]

N+1 mean you keep one backup WLC for N number of WLCs. In this method AP has to register with back up controller when its primary WLC is down. So client sessions will be dropped and reconnect. In this method, there will be a downtime for clients while AP register to backup WLC.

https://www.cisco.com/c/en/us/td/docs/wireless/technology/hi_avail/N1_High_Availability_Deployment_Guide/N1_HA_Overview.html? 

SSO means Stateful Switch Over. In this method, you have to have a pair of WLC (one in active mode the other one in standby). In this method, standby WLC will sync with the Active unit and during a failure of Active WLC, all sessions (AP & Clients) tastefully switchover to the standby Unit. So the client point of view, will not feel any difference during this failover.

https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-1/HA_SSO_DG/High_Availability_DG.html? 

HTH

Rasika

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[Farhad Tavakoli]

what is the N+1 with SSO deployment? 

[Mark Elsen]

  - N+1 : APs need to be configured with a primary and backup controller

 - HA SSO :  failure of one controller results in automatic failover to the standby controller : 
                                       clients and APs are not impacted ,

 M.