Interlogix GE-DS-242-PoE User Manual page 120

Chapter 4: Web-Based Management
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.)
 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.
 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.
 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.
116 GE-DS-242-PoE Managed Ethernet Switch User Manual