3com 5500-SI Manual Do Utilizador

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C
HAPTER
 21: 802.1
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 C
ONFIGURATION
returns the configuration information and accounting data to NAS. Here, NAS 
controls users and corresponding connections, while the RADIUS protocol 
regulates how to transmit configuration and accounting information between 
NAS and RADIUS. 
NAS and RADIUS exchange the information with UDP packets. During the 
interaction, both sides encrypt the packets with keys before uploading user 
configuration information (for example, password) to avoid being intercepted or 
stolen.
RADIUS Operation
A RADIUS server generally uses proxy function of the devices such as an access 
server to perform user authentication. The operation process is as follows: First, 
the user sends a request message (the client username and encrypted password is 
included in the message ) to the RADIUS server. Second, the user will receive from 
the RADIUS server various kinds of response messages in which the ACCEPT 
message indicates that the user has passed the authentication, and the REJECT 
message indicates that the user has not passed the authentication and needs to 
input their username and password again, otherwise they will be rejected access. 
Implementing
AAA/RADIUS on the
Ethernet Switch
In the above-mentioned AAA/RADIUS framework, the Switch 5500 Family, serving 
as the user access device or NAS, is the client end of RADIUS. In other words, the 
AAA/RADIUS concerning the client-end is implemented on the Switch 5500. 
Figure 107 illustrates the RADIUS authentication network including 5500 
Switches.
Figure 107   Networking when Switch 5500 Units are Applying RADIUS Authentication 
Configuring AAA
AAA configuration includes:
Creating/deleting an ISP domain
Configuring relevant attributes of the ISP domain
Creating a local user
Setting attributes of the local user
Disconnecting a user by force
 
Internet
Internet
SW 5500
PC user1
PC user2
PC user3
 
PC user4
 
SW 5500 
ISP1
ISP2
Authentication
 
Server
 
Accounting
 
Server
 
Authentication
 
Server
 
Accounting
 
Server1
 
Accounting
 
Server2
 
Internet