Table 129 The RADIUS server returns a stop-accounting response (Accounting-Response) and stops accounting for the user.

Table 130 The user stops access to network resources.

RADIUS packet format

RADIUS uses UDP to transmit messages. It ensures the smooth message exchange between the RADIUS server and the client through a series of mechanisms, including the timer management mechanism, retransmission mechanism, and slave server mechanism.

a.RADIUS packet format

Descriptions of the fields are as follows:

Table 131 The Code field (1-byte long) indicates the type of the RADIUS packet.

2.Main values of the Code field

Code

Packet type

Description

 

 

 

 

 

From the client to the server. A packet of this type carries user

1

Access-Request

information for the server to authenticate the user. It must contain the

User-Name attribute and can optionally contain the attributes of

 

 

 

 

NAS-IP-Address, User-Password, and NAS-Port.

 

 

 

 

 

From the server to the client. If all the attribute values carried in the

2

Access-Accept

Access-Request are acceptable, that is, the authentication succeeds,

 

 

the server sends an Access-Accept response.

 

 

 

 

 

From the server to the client. If any attribute value carried in the

3

Access-Reject

Access-Request is unacceptable, the server rejects the user and sends

 

 

an Access-Reject response.

 

 

 

 

 

From the client to the server. A packet of this type carries user

4

Accounting-Request

information for the server to start/stop accounting for the user. It

contains the Acct-Status-Type attribute, which indicates whether the

 

 

 

 

server is requested to start the accounting or to end the accounting.

 

 

 

 

 

From the server to the client. The server sends to the client a packet of

5

Accounting-Response

this type to notify that it has received the Accounting-Request and has

 

 

correctly started recording the accounting information.