3Com 4210 PWR Configuration Manual page 243

Figure 79 RADIUS message format
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Code
1 The Code field (one byte) decides the type of RADIUS message, as shown in
Table 178.
Table 178 Description of the major values of the Code field
Code Message type
1 Access-Request
2 Access-Accept
3 Access-Reject
4 Accounting-Request
5 Accounting-Response
2 The Identifier field (one byte) is used to match requests and responses. It changes
whenever the content of the Attributes field changes, and whenever a valid
response has been received for a previous request, but remains unchanged for
message retransmission.
Introduction to AAA Services
15
Identifier
Authenticator
Attribute
Message description
Direction: client->server.
The client transmits this message to the server to
determine if the user can access the network.
This message carries user information. It must contain
the User-Name attribute and may contain the
following attributes: NAS-IP-Address, User-Password
and NAS-Port.
Direction: server->client.
The server transmits this message to the client if all
the attribute values carried in the Access-Request
message are acceptable (that is, the user passes the
authentication).
Direction: server->client.
The server transmits this message to the client if any
attribute value carried in the Access-Request message
is unacceptable (that is, the user fails the
authentication).
Direction: client->server.
The client transmits this message 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
message).
This message carries almost the same attributes as
those carried in the Access-Request message.
Direction: server->client.
The server transmits this message to the client to
notify the client that it has received the
Accounting-Request message and has correctly
recorded the accounting information.
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