3Com Switch 7750 Configuration Guide Guide

Overview 489
management, retransmission, and backup server. Figure 126 depicts the structure
of the RADIUS packets.
Figure 126 RADIUS packet structure
1 The Code field decides the type of the RADIUS packet, as shown in Table 370.
2 The Identifier field (one byte) identifies the request and response packets. It is
subject to the Attribute field and varies with the received valid responses, but
keeps unchanged during retransmission.
3 The Length field (two bytes) specifies the total length of the packet (including the
Code, Identifier, Length, Authenticator and Attribute fields). The bytes beyond the
length will be regarded as padding bytes and are ignored upon receiving the
packet. If the received packet is shorter than the value of this field, it will be
discarded.
Code
Identifier Length
Authenticator
Attribute
Table 370 Description on major values of the Code field
Code Packet type Packet description
1 Access-Request
Direction: client->server.
The client transmits this packet to the server to determine if
the user can access the network.
This packet carries user information. It must contain the
User-Name attribute and may contain the following
attributes: NAS-IP-Address, User-Password and NAS-Port.
2 Access-Accept
Direction: server->client.
The server transmits this packet to the client if all the
attribute values carried in the Access-Request packet are
acceptable (that is, the user passes the authentication).
3 Access-Reject
Direction: server->client.
The server transmits this packet to the client if any attribute
value carried in the Access-Request packet is unacceptable
(that is, the user fails the authentication).
4
Accounting-Reques
t
Direction: client->server.
The client transmits this packet to the server to request the
server to start or end the accounting (whether to start or to
end the accounting is determined by the Acct-Status-Type
attribute in the packet).
This packet carries almost the same attributes as those carried
in the Access-Request packet.
5
Accounting-Respon
se
Direction: server->client.
The server transmits this packet to the client to notify the
client that it has received the Accounting-Request packet and
has correctly recorded the accounting information.