Appendix B 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.

 

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NWA-3500/NWA-3550 User’s Guide