H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 439)

38-4
Figure 38-3 RADIUS packet format
Descriptions of the fields are as follows:
1) The Code field (1-byte long) is for indicating the type of the RADIUS packet. Table 38-1 gives the
possible values and their meanings.
Table 38-1 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/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.
5 Accounting-Response
From the server to the client. The server sends to the client a packet of
this type to notify that it has received the Accounting-Request and has
correctly started recording the accounting information.
2) The Identifier field (1-byte long) is for matching request packets and response packets and
detecting retransmitted request packets. The request and response packets of the same type have
the same identifier.
3) The Length field (2-byte long) indicates the length of the entire packet, including the Code,
Identifier, Length, Authenticator, and Attribute fields. The value of the field is in the range 20 to
4096. Bytes beyond the length are considered the padding and are neglected upon reception. If the
length of a received packet is less than that indicated by the Length field, the packet is dropped.
4) The Authenticator field (16-byte long) is used to authenticate replies from the RADIUS server, and
is also used in the password hiding algorithm. There are two kinds of authenticators: request
authenticator and response authenticator.
5) The Attribute field, with a variable length, carries the specific authentication, authorization, and
accounting information for defining configuration details of the request or response. This field is
represented in triplets of Type, Length, and Value.