The Greek Research Network (GRNET) has been developing central video-conferencing services at the national level for the academic and research community. The main points of action of the project are: a scheduling interface for facilitating the organization of meetings through automated invitations to conferences and for managing MCU and Gateway resource reservation. The web interface is based on Apache/PHP/MySQL/LDAP. Authentication mechanisms for securing endpoint participation in specific, scheduled meetings are applied. The techniques involve gatekeeper interaction with RADIUS, MySQL, and LDAP, as well as the Cisco MCM GKAPI which has been explored as a means of controlling ARQs targeting scheduled MCU calls from legitimate, registered participants. Also, limited SNMP management of MCU conferences through a web interface has been implemented.