Device Roles - Cisco 6500 Series Software Configuration Manual

Understanding 802.1X Port-Based Authentication

Device Roles

With 802.1X port-based authentication, the devices in the network have specific roles as shown in
Figure
Figure 25-1 802.1X Device Roles
Workstations
(clients)
The specific roles shown in
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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
25-2
25-1.
Catalyst switch
Cisco Router
Figure 25-1
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.)
To resolve Windows XP network connectivity and 802.1X port-based authentication issues,
Note
read the Microsoft Knowledge Base article at this URL:
http://support.microsoft.com/support/kb/articles/Q303/5/97.ASP
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. 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
uses a client-server model in which secure authentication information is exchanged between the
RADIUS server and one or more RADIUS clients.
Switch (also called the authenticator and back-end authenticator)—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 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 reencapsulated 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.
Chapter 25
Authentication
server
or
(RADIUS)
are as follows:
Configuring IEEE 802.1X Port-Based Authentication
78-14099-04