Preamble Type - ZyXEL Communications B-220 User Manual

ZyAIR Wireless LAN Utility
Open authentication 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 authentication mode involves a shared secret key to authenticate the wireless station to the AP. This
requires you to enable a security feature and specify a shared secret key (usually the WEP encryption and
WEP key) on both the wireless station and the AP.
Auto authentication mode allows the ZyAIR to switch between the open and shared key authentication
modes automatically. Use the auto mode if you do not know the authentication mode of the other wireless
clients.
2.6

Preamble Type

A preamble is used to synchronize the transmission timing in your wireless network. There are two
preamble modes: Long Preamble and Short Preamble.
Short preamble takes less time to process and minimizes overhead, so it should be used in a good wireless
network environment when all wireless clients support it.
Select Long Preamble if you have a 'noisy' network or are unsure of what preamble mode the access point
or the other wireless clients support as all IEEE 802.11b compliant wireless adapters must support long
preamble. However, not all wireless adapters support short preamble. Use long preamble if you are unsure
what preamble mode the wireless adapters support, to ensure interpretability between the ZyAIR and the
access point/wireless stations and to provide more reliable communication in 'noisy' networks.
Select Auto to have the ZyAIR automatically use short preamble when all access point/wireless stations
support it, otherwise the ZyAIR uses long preamble.
The ZyAIR and the access point/wireless stations MUST use the same preamble mode in order to
communicate.
Wireless LAN 2-7