Home > Storage > PowerScale (Isilon) > Product Documentation > Management and Migration > PowerScale OneFS Authentication, Identity Management, and Authorization > Introduction
At the core of the Unified Permission Model is the OneFS Authentication, Identity Management, and Authorization (AIMA) model. Upon initial client connection to the cluster, information passes through the AIMA stack, which includes Directory Services, User Mapping, ID Mapping, Tokens, OnDisk ID, File Permissions, and ACL Policies, as illustrated in the following figure:
Figure 6. PowerScale OneFS AIMA
All the components of the AIMA stack work together to complete a user’s access experience and determine if access is granted to a file. Understanding the AIMA stack provides the basis for the OneFS implementation of multi-protocol. The AIMA stack is the focus of this paper.