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Appendix E Wireless LANs
IEEE 802.1x
In June 2001, the IEEE 802.1x standard was designed to extend the features of IEEE 802.11 to
support extended authentication as well as providing additional accounting and control features. It
is supported by Windows XP and a number of network devices. Some advantages of IEEE 802.1x
are:
• User based identification that allows for roaming.
• Support for RADIUS (Remote Authentication Dial In User Service, RFC 2138, 2139) for
centralized user profile and accounting management on a network RADIUS server.
• Support for EAP (Extensible Authentication Protocol, RFC 2486) that allows additional
authentication methods to be deployed with no changes to the access point or the wireless
clients.
RADIUS
RADIUS is based on a client-server model that supports authentication, authorization and
accounting. The access point is the client and the server is the RADIUS server. The RADIUS server
handles the following tasks:
• Authentication
Determines the identity of the users.
• Authorization
Determines the network services available to authenticated users once they are connected to the
network.
• Accounting
Keeps track of the client's network activity.
RADIUS is a simple package exchange in which your AP acts as a message relay between the
wireless client and the network RADIUS server.
Types of RADIUS Messages
The following types of RADIUS messages are exchanged between the access point and the RADIUS
server for user authentication:
• Access-Request
Sent by an access point requesting authentication.
• Access-Reject
Sent by a RADIUS server rejecting access.
• Access-Accept
Sent by a RADIUS server allowing access.
• Access-Challenge
Sent by a RADIUS server requesting more information in order to allow access. The access point
sends a proper response from the user and then sends another Access-Request message.
The following types of RADIUS messages are exchanged between the access point and the RADIUS
server for user accounting:
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VMG1312-B10B / VMG1312-B30B Series User's Guide
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