= Concepts

The Concepts guide introduces the main concepts for readers who are new to RADIUS (Remote Authentication Dial-In User Service) and its associated components.  This information explains the foundational ideas and principles behind RADIUS to help you understand what RADIUS is, what it does, and how it operates within a network environment. By covering these basics, the section aims to provide a solid starting point for further exploration or practical use of RADIUS in network authentication, authorization, and accounting.

== Sections in this Guide

* xref:concepts:overview.adoc[Overview] explains the RADIUS server, FreeRADIUS, and the core services provided.
        ** xref:freeradius.adoc[What is FreeRADIUS] explains the benefits of the open-source software version.
        ** xref:aaa/aaa.adoc[Authentication Authorisation Accounting (AAA)] explains the core services provided by FreeRADIUS.
                *** xref:aaa/authz.adoc[Authorisation] is the process of allowing an authenticated user to access services on the network.
                *** xref:aaa/authn.adoc[Authentication] if the process of verifying an end-user's credentials.
                *** xref:aaa/acct.adoc[Accounting] operations record the time spent on the network and services accessed for auditing or billing purposes.
        ** xref:components/architecture.adoc[RADIUS System Components] explains the RADIUS design and components.
                *** xref:components/nas.adoc[Network Access Server (NAS)] outlines the NAS operations and access management.
                *** xref:components/radius_servers.adoc[RADIUS Server] describes the role of the server and how server policies work.
                *** xref:components/datastore.adoc[Datastores] details how datastores work and what's supported.
        ** xref:session/radius_session.adoc[RADIUS Sessions] explains session transmission and management or these session on the network.
                *** xref:session/radius_session_msg.adoc[Session Messages] details the format and content of session messages.
                *** xref:session/processing.adoc[Processing] outlines the flow of messages and how aaa services are implemented.
* xref:protocol/authproto.adoc[Protocols] defines the protocols used in the RADIUS environment.
* xref:modules/ldap/authentication.adoc[Authentication with LDAP] can be used by RADIUS servers to authenticate the network users.
        ** xref:modules/ldap/password_storage.adoc[Password Storage] explains the methods of how the user's information can be stored.
        ** xref:modules/ldap/novell.adoc[Integrate Novell] with RADIUS networks using LDAP.
* xref:resources.adoc[Resources] find more help, mailing lists, and related documentation to help learn about deploying FreeRADIUS.
