http://www.mikrotik.com/docs/ros/2.8/guide/aaa says
“Realm - If it is set in /radius menu, it is included in every RADIUS request as Mikrotik-Realm attribute.”
while the link in the same doc - http://www.mikrotik.com/Documentation/manual_2.8/dictionary.mikrotik says
ATTRIBUTE Realm 9 string Mikrotik
Which one is correct ?