3Com Switch 8800 Advanced Software V5 Configuration Guide

AAA, RADIUS and HWTACACS Configuration Overview 883
9 The subscriber stops network resource accessing.
RADIUS packet structure
RADIUS resides at the application layer in TCP/IP protocol suite. It defines the way
to exchange user information between the device and the ISP RADIUS server.
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.
Figure 258 shows the RADIUS packet structure.
Figure 258 RADIUS packet structure
Descriptions of fields are as follows:
1 The Code field (1-byte long) is for indicating the type of the RADIUS packet.
Table 36 gives the possible values and their meanings.
Code
Attribute
Identifier
0
7
Length
Authenticator
715 31
Tab le 36 Main values of the Code field
Code Packet type Description
1 Access-Request From the client to the server. A packet of this
type carries user 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.
2 Access-Accept From the server to the client. If all the attribute
values carried in the Access-Request are
acceptable, that is, the authentication
succeeds, the server sends an Access-Accept
response.
3 Access-Reject From the server to the client. If any attribute
value carried in the Access-Request is
unacceptable, the server rejects the user and
sends an Access-Reject response.
4 Accounting-Request From the client to the server. A packet of this
type carries user information for the server to
start accounting on 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.