3com 5500-SI Manual Do Utilizador

Página de 686
21
802.1
X
 C
ONFIGURATION
This chapter covers the following topics:
For information on setting up a RADIUS server and RADIUS client refer to Appendix B.
For details on how to authenticate the Switch5500 with a Cisco Secure ACS server 
with TACACS+, refer to Appendix C.
IEEE 802.1x Overview
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 the LANs complying with the IEEE 802 standards, the user can access the devices 
and share the resources in the LAN through connecting the LAN access control device 
like the LAN Switch. However, in telecom access, commercial LAN (a typical example 
is the LAN in the office building) and mobile office and so on, the LAN providers 
generally hope to control the user's access. In these cases, the requirement on the 
above-mentioned “Port Based Network Access Control” originates. 
As the name implies, "Port Based Network Access Control" means to authenticate 
and control all the accessed devices on the port of LAN access control device. If the 
user's device connected to the port can pass the authentication, the user can access 
the resources in the LAN. Otherwise, the user cannot access the resources in the LAN. 
It equals that the user is physically disconnected.
802.1x defines port based network access control protocol and only defines the 
point-to-point connection between the access device and the access port. The port 
can be either physical or logical. The 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 defined by the IEEE 
802.11 standard (based on the logical port).
802.1x System
Architecture
The system using the 802.1x is the typical C/S (Client/Server) system architecture. It 
contains three entities, which are illustrated in Figure 104: Supplicant System (User), 
Authenticator System and Authentication Server System.
The LAN access control device needs to provide the Authenticator System of 802.1x. 
The devices at the user side such as the computers need to be installed with the 
802.1x client Supplicant (User) software, for example, the 802.1x client provided by 
3Com (or by Microsoft Windows XP). The 802.1x Authentication Server system 
normally stays in the carrier's AAA center.