Planet IGS-5225 Series User Manual page 324

Authentication Initiation and Message Exchange

The switch or the client can initiate authentication. If you enable authentication on a port by using the dot1x
port-control auto interface configuration command, the switch must initiate authentication when it
determines that the port link state transitions from down to up. It then sends an EAP-request/identity frame to
the client to request its identity (typically, the switch sends an initial identity/request frame followed by one or
more requests for authentication information). Upon receipt of the frame, the client responds with an
EAP-response/identity frame.
However, if during bootup, the client does not receive an EAP-request/identity frame from the switch, the
client can initiate authentication by sending an EAPOL-start frame, which prompts the switch to request the
client's identity
If 802.1X is not enabled or supported on the network access device, any EAPOL frames from the
client are dropped. If the client does not receive an EAP-request/identity frame after three attempts
to start authentication, the client transmits frames as if the port is in the authorized state. A port in
the authorized state effectively means that the client has been successfully authenticated.
When the client supplies its identity, the switch begins its role as the intermediary, passing EAP frames between the client and
the authentication server until authentication succeeds or fails. If the authentication succeeds, the switch port becomes
authorized.
The specific exchange of EAP frames depends on the authentication method being used.
exchange initiated by the client using the One-Time-Password (OTP) authentication method with a RADIUS server.
Ports in Authorized and Unauthorized States

The switch port state determines whether or not the client is granted access to the network. The port starts in
Figure 4-5-2-2: EAP Message Exchange
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User's Manual of IGS-5225 series
"Figure 4-5-2" shows a message