checksimul callback

Hello! I'm writing my own module. What is the purpose of checksimul callback? When is it called? The prototype of this function is static int rlm_myrlm_checksimul(void *instance, REQUEST * request); hence it should modify something in request. Likely simul_count field. What function checks this (or maybe another) field? How can I set the maximum number of simultaneous sessions? Thank you beforehand! -- Sincerely yours, Dmitry V. Krivenok Orange System Company Saint-Petersburg, Russia work phone: +7 812 332-32-40 cellular phone: +7 921 576-70-91 e-mail: krivenok@orangesystem.ru web: http://www.orangesystem.ru skype: krivenok_dmitry jabber: krivenok_dmitry@jabber.ru icq: 242-526-443