radius - technical definition

A straight line extending from the center of a circle to its edge, or from the center of a sphere to its surface. See also bend radius and radian.

An Internet protocol used for authentication, authorization, and accounting of end users seeking to gain access to internal computer resources, generally through a network access server (NAS) or, for remote users, by dialing into a remote access server (RAS). Originally developed by Livingston Enterprises, RADIUS was later described by the IETF in RFCs 2058 and 2059 and is currently described in RFCs 2865 and 2866. See also authentication, authorization, IETF, NAS, RAS, and RFC.