NETGEAR Double 108 Mbps Wireless PC Card WG511U User Manual
Page 68
User’s Manual for the NETGEAR Double 108 Mbps Wireless PC Card 32-bit CardBus WG511U
B-16
Wireless Networking Basics
August 2004
Figure B-5: WPA Overview
The strength WPA comes from an integrated sequence of operations that encompass 802.1X/EAP
authentication and sophisticated key management and encryption techniques. Its major operations
include:
•
Network security capability determination. This occurs at the 802.11 level and is
communicated through WPA information elements in Beacon, Probe Response, and (Re)
Association Requests. Information in these elements includes the authentication method
(802.1X or Pre-shared key) and the preferred cipher suite (WEP, TKIP, or AES).
The primary information conveyed in the Beacon frames is the authentication method and the
cipher suite. Possible authentication methods include 802.1X and Pre-shared key. Pre-shared
key is an authentication method that uses a statically configured pass phrase on both the
stations and the access point. This eliminates the need for an authentication server, which in
many home and small office environments will not be available nor desirable. Possible data
encryption options include: WEP, TKIP, and AES (Advanced Encryption Standard). We’ll talk
more TKIP and AES when addressing data privacy below.
•
Authentication. EAP over 802.1X is used for authentication. Mutual authentication is gained
by choosing an EAP type supporting this feature and is required by WPA. 802.1X port access
control prevents full access to the network until authentication completes. 802.1X
EAPOL-Key packets are used by WPA to distribute per-session keys to those stations
successfully authenticated.
WPA
enabled
wireless
client with
“supplicant”
Optional
Certificate
Authority
(eg Win
Server,
VeriSign,
etc)
TCP/IP
Ports Closed
Until
RADIUS Server
Wired Network with Optional
WPA 802.1x Port Based
Network Access Control
WPA enabled
Access Point
using
pre-shared key
or
802.1x/EAP
TCP/IP
Ports Opened
After
Authenticated
Wireless Network
Login
Authentication