Eap over radius, Eap-message, Message-authenticator – H3C Technologies H3C WX3000E Series Wireless Switches User Manual
Page 121: Initiating 802.1x authentication, 1x client as the initiator, Access device as the initiator

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EAP over RADIUS
RADIUS adds two attributes, EAP-Message and Message-Authenticator, for supporting EAP
authentication. For the RADIUS packet format, see "Configuring AAA."
EAP-Message
RADIUS encapsulates EAP packets in the EAP-Message attribute, as shown in
. The Type field
takes 79, and the Value field can be up to 253 bytes. If an EAP packet is longer than 253 bytes, RADIUS
encapsulates it in multiple EAP-Message attributes.
Figure 56 EAP-Message attribute format
Message-Authenticator
RADIUS includes the Message-Authenticator attribute in all packets that have an EAP-Message attribute
to check their integrity. The packet receiver drops the packet if the calculated packet integrity checksum
is different than the Message-Authenticator attribute value. The Message-Authenticator prevents EAP
authentication packets from being tampered with during EAP authentication.
Figure 57 Message-Authenticator attribute format
Initiating 802.1X authentication
Both the 802.1X client and the access device can initiate 802.1X authentication.
802.1X client as the initiator
The client sends an EAPOL-Start packet to the access device to initiate 802.1X authentication. The
destination MAC address of the packet is the IEEE 802.1X specified multicast address
01-80-C2-00-00-03 or the broadcast MAC address. If any intermediate device between the client and
the authentication server does not support the multicast address, you must use an 802.1X client, the H3C
iNode 802.1X client for example, that can send broadcast EAPOL-Start packets.
Access device as the initiator
The access device initiates authentication, if a client, the 802.1X client available with Windows XP for
example, cannot send EAPOL-Start packets.
The access device supports the following modes:
•
Multicast trigger mode—The access device multicasts Identity EAP-Request packets periodically
(every 30 seconds by default) to initiate 802.1X authentication.
- H3C WX5500E Series Access Controllers H3C WX3500E Series Access Controllers H3C WX2500E Series Access Controllers H3C WX6000 Series Access Controllers H3C WX5000 Series Access Controllers H3C LSWM1WCM10 Access Controller Module H3C LSUM3WCMD0 Access Controller Module H3C LSUM1WCME0 Access Controller Module H3C LSWM1WCM20 Access Controller Module H3C LSQM1WCMB0 Access Controller Module H3C LSRM1WCM2A1 Access Controller Module H3C LSBM1WCM2A0 Access Controller Module H3C WA3600 Series Access Points H3C WA2600 Series WLAN Access Points H3C S10500 Series Switches H3C S5800 Series Switches H3C S5820X Series Switches H3C S12500 Series Switches H3C S9500E Series Switches H3C MSR 5600 H3C MSR 50 H3C MSR 3600 H3C MSR 30 H3C MSR 2600 H3C MSR 20-2X[40] H3C MSR 20-1X H3C MSR 930 H3C MSR 900 H3C SR8800 H3C SR6600-X H3C SR6600 H3C SecPath F5020 H3C SecPath F5040 H3C VMSG VFW1000