ZyXEL Communications max208m User Manual

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Appendix A WiMAX Security
WiMAX Device Configuration User’s Guide
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• 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 base station acts as a message relay between 
the MS/SS and the network RADIUS server. 
Types of RADIUS Messages
The following types of RADIUS messages are exchanged between the base station and the RADIUS 
server for user authentication:
• Access-Request
Sent by an base station 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 base station 
sends a proper response from the user and then sends another Access-Request message. 
The following types of RADIUS messages are exchanged between the base station and the RADIUS 
server for user accounting:
• Accounting-Request
Sent by the base station requesting accounting.
• Accounting-Response
Sent by the RADIUS server to indicate that it has started or stopped accounting. 
In order to ensure network security, the access point and the RADIUS server use a shared secret 
key, which is a password they both know. The key is not sent over the network. In addition to the 
shared key, password information exchanged is also encrypted to protect the network from 
unauthorized access. 
Diameter
Diameter (RFC 3588) is a type of AAA server that provides several improvements over RADIUS in 
efficiency, security, and support for roaming. 
Security Association
The set of information about user authentication and data encryption between two computers is 
known as a security association (SA). In a WiMAX network, the process of security association has 
three stages.