When Radius is in use login failure does not log if its due to wrong credentials or to radius unavailability
Summary
When Radius server is down it is not visible that login failure is related to unavailability LLNG reports error PE_BADCREDENTIALS.
To test :
on a working environment using radius log in successfully, then either stop radius server or block UDP radius traffic between LLNG and radius server. Log out then login again, it will fail like if credentials are wrong, and logs at server side will report PE_BADCREDENTIALS.
Design proposition
Log at server side should report a new specific error like PE_RADIUSUNAVAILABLE.