Encryption Type; Preamble Type; Figure 12 Wpa(2) With Radius Application Example - ZyXEL Communications ZyXEL ZyWALL 1 User Manual

Figure 12 WPA(2) with RADIUS Application Example

2.3 Encryption Type

The IEEE 802.11b/g standard describes a simple encryption method between the wireless
stations and AP. Three encryption types are defined: Auto, Open System and Shared Key.
• Open System mode is implemented for ease-of-use and when security is not an issue.
The wireless station and the AP do not share a secret key. Thus the wireless stations can
associate with any AP and listen to any data transmitted plaintext.
• Shared Key mode involves a shared secret key to authenticate the wireless station to the
AP. This requires you to enable the wireless LAN security and use same settings on both
the wireless station and the AP.
• Auto authentication mode allows the ZyXEL G-220 v2 to switch between the open
system and shared key modes automatically. Use the auto mode if you do not know the
authentication mode of the other wireless stations.

2.4 Preamble Type

Preamble is used to signal that data is coming to the receiver.
Short preamble increases performance as less time sending preamble means more time for
sending data. All IEEE 802.11b/g compliant wireless adapters support long preamble, but not
all support short preamble.
Select Long preamble if you are unsure what preamble mode the wireless adapters support,
and to provide more reliable communications in busy wireless networks.
Select Short preamble if you are sure the wireless adapters support it, and to provide more
efficient communications.
Chapter 2 Wireless LAN Network
ZyXEL G-220 v2 User's Guide
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