omran almuhesen,
What does not work?
That could be a symptom of a connectivity issue in your network. Connectivity between master and local controllers is used to:
- Synchroize configurations (only used every time you type "write mem" or save the configuration)
- Authenticate Local Guest Users that are created in the master controller
- Authenticate RAP devices (If 6.3 and above, this is distributed and always-on connectivity is needed between controllers)
Besides those things, each controller operates on its own and should be able to authenticate users and pass traffic even if the other controller is down or cannot be reached.
Again, what function does not work, when this happens?