Planet Technology IP DSLAM IDL-4801 - Manual (Page 702)

IDL series User Guide 702
Authenticcation Initiation and Message Exchange
The host initiate authentication by sending an EAPOL-start frame, which prompts the
DSLAM to request the host's identity.
When the host supplies its identity, the DSLAM acts as the intermediary, pass EAP frames
between the host and the authentication server until authentication succeeds or fails. If the
authentication succeeds, the DSLAM port becomes authorized.
The specific exchange of EAP frames depends on the authentication method that is being
used. The below fiugre shows a message exchange that is initiated by the host using the
One-Time-Password (OTP) authentication method with a RADIUS server.