ZyXEL Communications MAX-706 User Manual page 52

Appendix B WiMAX Security
• 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 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.
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MAX-706 User's Guide