HP 4800G Series Configuration Manual page 1235

Figure 1-3 EAPOL frame format
PAE Ethernet type: Protocol type. It takes the value 0x888E.
Protocol version: Version of the EAPOL protocol supported by the EAPOL frame sender.
Type: Type of the EAPOL frame.
Table 1-1 Types of EAPOL frames
Type
EAP-Packet (a value of 0x00)
EAPOL-Start (a value of 0x01)
EAPOL-Logoff (a value of 0x02)
Length: Length of the data, that is, length of the Packet body field, in bytes. If the value of this field
is 0, no subsequent data field is present.
Packet body: Content of the packet. The format of this field varies with the value of the Type field.
EAP Packet Format
An EAPOL frame of the type of EAP-Packet carries an EAP packet in its Packet body field. The format
of the EAP packet is shown in
Figure 1-4 EAP packet format
0 7
Code
Length
Data
Code: Type of the EAP packet, which can be Request, Response, Success, or Failure.
An EAP packet of the type of Success or Failure has no Data field, and has a length of 4.
An EAP packet of the type of Request or Response has a Data field in the format shown in
The Type field indicates the EAP authentication type. A value of 1 represents Identity, indicating that the
packet is for querying the identity of the client. A value of 4 represents MD5-Challenge, which
corresponds closely to the PPP CHAP protocol.
Table 1-1 lists the types that the device currently supports.
Frame for carrying authentication information, present between
a device and the authentication server.
A frame of this type is repackaged and transferred by RADIUS
to get through complex networks to reach the authentication
server.
Frame for initiating authentication, present between a client and
a device.
Frame for logoff request, present between a client and a device.
Figure 1-4.
15
Identifier
2
4
N
1-4
Description
Figure 1-5.