NETGEAR ProSafe FWAG114, Справочное руководство

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Reference Manual for the ProSafe Dual Band Wireless VPN Firewall FWAG114
Wireless Networking Basics D-3
The ESSID is usually broadcast in the air from an access point. The wireless station sometimes can
be configured with the ESSID
ANY. This means the wireless station will try to associate with
whichever access point has the stronger radio frequency (RF) signal, providing that both the access
point and wireless station use Open System authentication.
Authentication and WEP Data Encryption
The absence of a physical connection between nodes makes the wireless links vulnerable to
eavesdropping and information theft. To provide a certain level of security, the IEEE 802.11
standard has defined these two types of authentication methods:
• Open System . With Open System authentication, a wireless PC can join any network and
receive any messages that are not encrypted.
• Shared Key . With Shared Key authentication, only those PCs that possess the correct
authentication key can join the network. By default, IEEE 802.11 wireless devices operate in
an Open System network.
Wired Equivalent Privacy (WEP) data encryption is used when the wireless devices are configured
to operate in Shared Key authentication mode.
802.11 Authentication
The 802.11 standard defines several services that govern how two 802.11 devices communicate.
The following events must occur before an 802.11 Station can communicate with an Ethernet
network through an access point such as the one built in to the FWAG114:
1.
Turn on the wireless station.
2.
The station listens for messages from any access points that are in range.
3.
The station finds a message from an access point that has a matching SSID.
4.
The station sends an authentication request to the access point.
5.
The access point authenticates the station.
6.
The station sends an association request to the access point.
7.
The access point associates with the station.
8.
The station can now communicate with the Ethernet network through the access point.