3com 4210 PWR 9-Port 3CR17341-91-ME User Manual

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HAPTER

 17: 802.1

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ONFIGURATION

In an EAPoL packet:

■

The PAE Ethernet type field holds the protocol identifier. The identifier for 
802.1x is 0x888E.

■

The Protocol version field holds the version of the protocol supported by the 
sender of the EAPoL packet.

■

The Type field can be one of the following:

00: Indicates that the packet is an EAP-packet, which carries authentication 
information.

01: Indicates that the packet is an EAPoL-start packet, which initiates the 
authentication.

02: Indicates that the packet is an EAPoL-logoff packet, which sends logging 
off requests.

03: Indicates that the packet is an EAPoL-key packet, which carries key 
information.

04: Indicates that the packet is an EAPoL-encapsulated-ASF-Alert packet, 
which is used to support the alerting messages of ASF (alerting standards 
forum).

■

The Length field indicates the size of the Packet body field. A value of 0 
indicates that the Packet Body field does not exist.

■

The Packet body field differs with the Type field.

Note that EAPoL-Start, EAPoL-Logoff, and EAPoL-Key packets are only transmitted 
between the supplicant system and the authenticator system. EAP-packets are 
encapsulated by RADIUS protocol to allow them successfully reach the 
authentication servers. Network management-related information (such as 
alarming information) is encapsulated in EAPoL-Encapsulated-ASF-Alert packets, 
which are terminated by authenticator systems.

For an EAPoL packet with the value of the Type field being EAP-packet, its Packet 
body field is an EAP packet, whose format is illustrated in Figure 68.

Figure 68   The format of an EAP packet

In an EAP packet:

■

The Code field indicates the EAP packet type, which can be Request, Response, 
Success, or Failure.

■

The Identifier field is used to match a Response packet with the corresponding 
Request packet.

0

15

Code

Data

Length

7

Identifier

2

4

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