Single Sign-On (SSO) is an authentication scheme that permits a user to log in with a single ID to any of several related, yet independent, systems. It allows the user to log in once and access services without re-entering authentication credentials. SSO solutions are classified depending on Authentication, Authorization, and Accounting features. AAA is an acronym defining a framework for intelligently controlling access to resources, enforcing security policies, auditing usage, and providing the information necessary to bill for services. These combined processes are considered important for effective network management and security.