3Com 3C13636 Configuration Manual page 1004

3Com Router 3000 Ethernet Family
Configuration Guide
about RADIUS clients such as shared key; and "Dictionary" stores the information for
interpreting RADIUS protocol attributes and their values.
Users
Figure 2-1 Components of RADIUS server
In addition, RADIUS servers can act as the client of some other AAA servers to provide
the proxy authentication or accounting service. They support multiple user
authentication methods, such as PPP-based PAP, CHAP and UNIX-based login.
II. Basic message exchange procedures in RADIUS
In most cases, user authentication using a RADIUS server always involves a device
that can provide the proxy function, such as the NAS. Transactions between the
RADIUS client and RADIUS server are authenticated through a shared key, and user
passwords are sent encrypted over the network for the security sake. The RADIUS
protocol combines the authentication and authorization processes by sending
authorization information in the authentication response message. See the following
figure.
PC PC
The subscriber enters user name and password The subscriber enters user name and password
Notif y of the terminated access Notif y of the terminated access
Figure 2-2 The basic message interaction procedures of RADIUS
Following is how RADIUS operates:
1) The user enters the username and password.
RADIUS Server
Clients
RADIUS Client RADIUS Client
PSTN/ PSTN/
ISDN ISDN
/ /
Authentication Request ( Access-Request) Authentication Request ( Access-Request)
Authentication Accept(Access-Accept) Authentication Accept(Access-Accept)
The subscriber accesses the resources The subscriber accesses the resources
3Com Corporation
2-3
Chapter 2 AAA and RADIUS/HWTACACS Protocol
Dictionary
RADIUS Server RADIUS Server
Accounting-Request (start) Accounting-Request (start)
Accounting-Response Accounting-Response
Accounting-Request (stop) Accounting-Request (stop)
Accounting-Response Accounting-Response
Configuration