3Com WX3000 Basic message exchange procedure in Radius, 1Databases in a Radius server

zThe RADIUS server receives user connection requests, authenticates users, and returns all required information to the device.

Generally, a RADIUS server maintains the following three databases (see Figure 1-1):

zUsers: This database stores information about users (such as user name, password, protocol adopted and IP address).

zClients: This database stores information about RADIUS clients (such as shared key).

zDictionary: The information stored in this database is used to interpret the attributes and attribute values in the RADIUS protocol.

Figure 1-1Databases in a RADIUS server

RADIUS servers

User

Clients

Dictionary

In addition, a RADIUS server can act as a client of some other AAA server to provide authentication or accounting proxy service.

Basic message exchange procedure in RADIUS

The messages exchanged between a RADIUS client and a RADIUS server are verified through a shared key. This enhances the security. The RADIUS protocol combines the authentication and authorization processes together by sending authorization information along with the authentication response message. Figure 1-2 depicts the message exchange procedure between the user, device and RADIUS server.

Figure 1-2Basic message exchange procedure of RADIUS

Host RADIUS Client RADIUS Server

(1 )	The user inputs the user
	name and password
		( 2 ) Access -Request
		( 3 ) Access -Accept
	(4 )	Accounting-Request (start)
	( 5 )	Accounting-Response
	( 6 ) The user begins to access resources
	( 7 ) Accounting-Request (stop)
	( 8 )	Accounting-Response
( 9 ) Inform the user the access is ended

The basic message exchange procedure of RADIUS is as follows:

1)The user enters the user name and password.

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