Operation Manual – 802.1x-System GuardH3C S3100 Series Ethernet Switches Chapter 1 802.1x Configuration1-50 15CodeDataLength7Identifier 24NFigure 1-4 The format of an EAP packetIn an EAP packet:z The Code field indicates the EAP packet type, which can be Request, Response,Success, or Failure.z The Identifier field is used to match a Response packet with the correspondingRequest packet.z The Length field indicates the size of an EAP packet, which includes the Code,Identifier, Length, and Data fields.z The Data field carries the EAP packet, whose format differs with the Code field.A Success or Failure packet does not contain the Data field, so the Length field of it is 4.Figure 1-5 shows the format of the Data field of a Request packet or a Responsepacket.Figure 1-5 The format of the Data field of a Request packet or a Response packetz The Type field indicates the EAP authentication type. A value of 1 indicatesIdentity and that the packet is used to query the identity of the peer. A value of 4represents MD5-Challenge (similar to PPP CHAP) and indicates that the packetincludes query information.z The Type Date field differs with types of Request and Response packets.III. Newly added fields for EAP authenticationTwo fields, EAP-message and Message-authenticator, are added to a RADIUSprotocol packet for EAP authentication. (Refer to the Introduction to RADIUS protocolsection in the AAA Operation Manual for information about the format of a RADIUSprotocol packet.)The EAP-message field, whose format is shown in Figure 1-6, is used to encapsulateEAP packets. The maximum size of the string field is 253 bytes. EAP packets with theirsize larger than 253 bytes are fragmented and are encapsulated in multipleEAP-message fields. The type code of the EAP-message field is 79.
