LANCOM GS
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Chapter 4: Operation of Web- based Management
38
EN
The following figure shows the procedure of 802.1x authentication. There are
steps for the login based on 802.1x port access control management. The pro-
tocol used in the right side is EAPOL and the left side is EAP.
쐃
At the initial stage, the supplicant A is unauthenticated and a port on
switch acting as an authenticator is in unauthorized state. So the access
is blocked in this stage.
쐇
Initiating a session. Either authenticator or supplicant can initiate the
message exchange. If supplicant initiates the process, it sends EAPOL-
start packet to the authenticator PAE and authenticator will immediately
respond EAP-Request/Identity packet.
쐋
The authenticator always periodically sends EAP-Request/Identity to the
supplicant for requesting the identity it wants to be authenticated.
쐏
If the authenticator doesn’t send EAP-Request/Identity, the supplicant will
initiate EAPOL-Start the process by sending to the authenticator.
쐄
And next, the Supplicant replies an EAP-Response/Identity to the authen-
ticator. The authenticator will embed the user ID into Radius-Access-
Request command and send it to the authentication server for confirming
its identity.
쐂
After receiving the Radius-Access-Request, the authentication server
sends Radius-Access-Challenge to the supplicant for asking for inputting
user password via the authenticator PAE.
쐆
The supplicant will convert user password into the credential information,
perhaps, in MD5 format and replies an EAP-Response with this credential
information as well as the specified authentication algorithm (MD5 or
OTP) to Authentication server via the authenticator PAE. As per the value
of the type field in message PDU, the authentication server knows which
algorithm should be applied to authenticate the credential information,
EAP-MD5 (Message Digest 5) or EAP-OTP (One Time Password) or other
else algorithm.
쐊
If user ID and password is correct, the authentication server will send a
Radius-Access-Accept to the authenticator. If not correct, the authentica-
tion server will send a Radius-Access-Reject.
쐎
When the authenticator PAE receives a Radius-Access-Accept, it will send
an EAP-Success to the supplicant. At this time, the supplicant is authori-
zed and the port connected to the supplicant and under 802.1x control is
