RADIUS explained

Remote Authentication Dial-In User Service (RADIUS) is a client-server protocol deplyed for remote authentication, authorisation and accountancy from (triple-A-system) users of a dial-up connection that serves some network. RADIUS is a widely used centralised standard for dial-up connections on most  common modems, ISDN, VPN, WLAN (IEEE 802.1X) and DSL. Its implementation is not as widely seen in common protocol diameters, which have come to include more broadly encompassing functions, but which aren't entirely backwards compatible.

That been said, it should be clear that a RADIUS server is the equivalent of an authentication server accountable for verifying one's username along with its matching password. It may work both on a physical, fully functional Ethernet standard network or a Virtual Private network such as RAS (Remote Access Services) for windows clients for instance, according to the type of configuration on the proxy server.

Username and password are taken as parameters for the connection  with the host client. It then employs information taken from the configuration data on the RADIUS server or even some data base configuration file determined through requests to further data bases or some directory service onto which access through username and password can be saved.


Out of these elements, regardless of the network infrastructure, the user-defined settings can be centrally managed. A RADIUS server could for instance speed up its own upstream and downstream data transfer on a DSL connection, the highest count of the B channel by ISDN or parameters like IP-, routing or MPLS parameters to be relayed to the RAS service.

CommonRADIUS features. Image retrieved from:http://www.cisco.com/en/US/tech/tk59/technologies_tech_note09186a0080094e99.shtml

A common advantage to this approach lies in the user's unmatched access records, scattered across the network overall and promptly available by means of simple administrative rights.from a centralised domain and liable for changes.

A RADIUS set up can be allowed to run automatically if it's combined with other web services such as DHCP and PPP.