In addition to the Security Models and Levels described above, the Extreme Networks implementation of SNMP also provides a View-based Access Control Model (VACM), which determines remote access to managed objects. VACM allows you to organize subsets of management information into “views.” Management information that is in a user's view gives the user the corresponding access level to that management information: either read, write, or notify. Individual users can be organized into groups for whom you can pre-define what views are available based on the security model and security level used to request access. In this way, VACM allows you to permit or deny access to any individual item of management information depending on a user's group membership and the level of security provided by the communications channel.