vCenter Single Sign-On constructs an
internal security domain (vsphere.local) where vSphere solutions and components are registered during
installation or upgrade, providing an infrastructure resource. vCenter Single Sign-On can authenticate users
from its own internal users and groups, or it can connect to trusted external directory services such as
Microsoft’s Active Directory. Authenticated users are then ready for assignment of registered solution-based
permissions and/or roles within a vSphere 5.5 environment.