RADIUS
A protocol that centralizes authentication for network access, used by wireless, VPN, and switch port control.
A RADIUS server checks credentials against a directory and tells the network device whether to permit access and under what policy. It is the engine behind 802.1X deployments.
Because it is central to network access, its availability matters. A single RADIUS server is a single point at which all wireless authentication stops.
Where this comes up
RADIUS sits inside our networks and infrastructure work. If you are trying to work out what this means for your own environment rather than in the abstract, that is the page worth reading next, and a short call will get you a straight answer faster than either.
Related terms
802.1X A standard requiring devices to authenticate before they are granted access to a wired or wireless network. VPN An encrypted tunnel that connects a remote user or site to a network as though they were locally attached. Active Directory Microsoft's on-premises directory service, running on domain controllers and governing Windows domain authentication.