[Kelly Crooks]

RADIUS- Remote Authentication Dial-In User Service.

Pros:
RADIUS is open-source and readily available
RADIUS utilizes the client/server model to authenticate and authorize users
Radius allows for unique credentials for each user
RADIUS passwords do not routine changing
RADIUS allows IT admins to have one point of contact for user management
RADIUS makes it easier to control who or what has access

Cons:
RADIUS uses connectionless protocol using UDP
RADIUS maintenance can be difficult and time-consuming
RADIUS initial setup can be difficult
RADIUS setup can be complicated
RADIUS can be hard to know which version is best to choose
RADIUS has options that can be costly and require long-term commitments

Some of RADIUS’s characteristics include the AAA protocol(Authentication, Authorization, Accounting, and Auditing). Cloud-based RADIUS a-as-a-Service offers similar capabilities. De facto standard for the authentication protocol. Open source means it has been integrated into many vendor products. RADIUS works on the client/server model. RADIUS is deemed connectionless since it is based on UDP.

The methods for centralized access control using RADIUS include:
The user connects to the server.
The access server requests authentication data from the user.
The RADIUS client sends authentication data to the RADIUS server.
RADIUS server compares data to the database.
RADIUS server sends the response.
If Accept is the response the RADIUS client allows the user to access the network.