Another important characteristic of ILIAS is the repository. All learning content but also forums or chat rooms, tests and surveys, as well as plugged in virtual classrooms or other external tools are created, offered and administrated in the repository and its categories. Therefore, it is not necessary to build up courses for offering learning content. ILIAS could also be used like a kind of knowledge base or website. Access to all repository item is granted by the role-based access control (RBAC) of ILIAS. The repository is structured as tree with a root node and multiple levels. Each repository item is assigned to one node in the RBAC tree.