Interlogix NS3503-16P-4C, Руководство пользователя

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NS3503-16P-4C User Manual
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Client —the device (workstation) that requests access to the LAN and switch services and responds
to requests from the switch. The workstation must be running 802.1X-compliant client software such
as that offered in the Microsoft Windows XP operating system. (The client is the supplicant in the
IEEE 802.1X specification.)
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Authentication server— performs the actual authentication of the client. The authentication server
validates the identity of the client and notifies the switch whether or not the client is authorized to
access the LAN and switch services. Because the switch acts as the proxy, the authentication
service is transparent to the client. In this release, the Remote Authentication Dial-In User Service
(RADIUS) security system with Extensible Authentication Protocol (EAP) extensions is the only
supported authentication server; it is available in Cisco Secure Access Control Server version 3.0.
RADIUS operates in a client/server model in which secure authentication information is exchanged
between the RADIUS server and one or more RADIUS clients.
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Switch (802.1X device) —controls the physical access to the network based on the authentication
status of the client. The switch acts as an intermediary (proxy) between the client and the
authentication server, requesting identity information from the client, verifying that information with
the authentication server, and relaying a response to the client. The switch includes the RADIUS
client, which is responsible for encapsulating and decapsulating the Extensible Authentication
Protocol (EAP) frames and interacting with the authentication server. When the switch receives
EAPOL frames and relays them to the authentication server, the Ethernet header is stripped and the
remaining EAP frame is re-encapsulated in the RADIUS format. The EAP frames are not modified or
examined during encapsulation, and the authentication server must support EAP within the native
frame format. When the switch receives frames from the authentication server, the server's frame
header is removed, leaving the EAP frame, which is then encapsulated for Ethernet and sent to the
client.
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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.
Note : 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.