I just need to confirm that is it possible that we add same WLC to CAS(wireless users) and NAC Guest Server(wireless guest users) or I must need one more WLC for NAC guest server.
You do not need seperate WLC's.. NAC guest servers are just normal radius servers, used for authentication. You can integrate your existing WLC's, which are added on IB or OOB to your CAS, with the guest server. I'm attaching a doc which gives info on how to setup wlc's and guest servers.
Hope this helps.. all the best.. happy new year to you. rate replies if found useful..