Planet Technology FGSW-2620VM User Manual

Page 55

FGSW-2620VM User’s Manual

• Authentication Initiation and Message Exchange

Device Roles

With 802.1X port-based authentication, the devices in the network have specific roles as shown below.

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