3com 3.01.01 User Manual

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9
AAA 
AND
 RADIUS O
PERATION
This chapter covers the following topics:
IEEE 802.1x
IEEE 802.1x (hereinafter simplified as 802.1x) is a port-based network access 
control protocol that is used as the standard for LAN user access authentication. 
In LANs that comply with IEEE 802 standards, the user can access devices and 
share resources in the LAN by connecting a device such as a LAN Switch. In 
telecom access, commercial LAN (a typical example is the LAN in the office 
building) and mobile office, etc., the LAN providers generally aim to control the 
user’s access. The requirement on the above-mentioned “port-based network 
access control” is the most applicable. 
As the name implies, “port-based network access control” means to authenticate 
and control all accessed devices on the port of the device. If the user’s device can 
pass authentication, the user can access resources in the LAN. 
802.1x defines port based network access control protocol, and the point-to-point 
connection between the access device and the access port, only. The port can be 
either physical or logical. A typical application environment is as follows: Each 
physical port of the LAN Switch only connects to one user workstation (based on 
the physical port) and the wireless LAN access environment (based on the logical 
port), etc. 
Configuring IEEE 802.1x is described in the following sections:
802.1x System 
Architecture
The system using 802.1x is a typical C/S (Client/Server) system architecture. It 
contains three entities, Supplicant System, Authenticator System and 
Authentication Server System.
The LAN access control device needs to provide the Authenticator System of 
802.1x. The computers need to be installed with the 802.1x client Supplicant 
software, for example, the 802.1x client provided by Microsoft Windows XP. The 
802.1x Authentication Server system normally stays in the carrier’s AAA center. 
Authenticator and Authentication Server exchange information through EAP 
(Extensible Authentication Protocol) frames. The Supplicant and the Authenticator 
exchange information through the EAPoL (Extensible Authentication Protocol over