hello.
how use ucs as external mikrotik radius server?
thanks
Without being more specific: Similar to any other RADIUS client. 
See: http://docs.software-univention.de/manual-4.4.html#ip-config:radius
You can either only define it manually in clients.conf of FreeRADIUS, or register and IP managed client in your Domain with the IP of your Mikrotik appliance and enable the RADIUS Authenticator option in the object in UMC.
If you need to send specific attributes such as VLANs or permissions within the answer from FreeRADIUS, you’ll have to customize the FreeRADIUS config. If all you need is checking credentials and getting an ACCESS-ACCEPT or ACCESS-REJECT from the RADIUS server, that should suffice.
thank you
i will try.