H3C S7500 Series Ethernet Switches Operation Manual

Operation Manual – 802.1x

H3C S7500 Series Ethernet Switches Chapter 1

802.1x Configuration

1-5

II. EAP packet format

For an EAPoL packet with the Type value being EAP-packet, the corresponding Packet

body is an EAP packet. Its format is illustrated in

Figure 1-4.

Code Identifier Length Data

Figure 1-4 The format of an EAP packe

In an EAP packet:

z The Code field specifies the EAP packet type, which can be Request, Response,

Success, or Failure.

z The Identifier field helps match Response and Request messages.

z The Length field indicates the size of an EAP packet, which includes the Code,

Identifier, Length, and Data fields.

z The Data field varies with the Code field.

A Success or Failure type EAP packet does not contain the Data field. Accordingly the

Length field is 4.

Figure 1-5 shows the format of Data field of Request and Response type packets.

Type Type Data

Figure 1-5 The format of Data field of Request and Response type packet

z The Type field specifies the EAP authentication type. A value of 1 represents

Identity, indicating that the packet is for querying the identity of the supplicant. A

value of 4 represents MD5 Challenge (similar to PPP CHAP protocol), including

query information.

z The Type Date field varies with different types of Request and Response packets.

III. EAP attribute encapsulation

Two attributes, EAP-message and Message-authenticator, are added for EAP

authentication. (For information about RADIUS packet format, refer to the Introduction

to RADIUS protocol section in AAA-RADIUS-HWTACACS-EAD Operation Manual.)

As shown in

Figure 1-6, the EAP-message attribute is used to encapsulate EAP

packets. The type code is 79. The maximum size of the string field is 253 bytes. EAP

packets with their sizes larger than 253 bytes are fragmented and stored in multiple

EAP-message fields orderly.