Authentication Type; Preamble Type - ZyXEL Communications ZyAIR G-220 User Manual

ZyAIR G-220 User's Guide
You should only configure RTS/CTS Threshold if the possibility of hidden nodes exists on your network
and the "cost" of resending large frames is more than the extra network overhead involved in the RTS
(Request To Send)/CTS (Clear to Send) handshake.
If the RTS/CTS Threshold value is greater than the Fragmentation Threshold value (see next), then the
RTS (Request To Send)/CTS (Clear to Send) handshake will never occur as data frames will be fragmented
before they reach RTS/CTS Threshold size.
Enabling the RTS Threshold causes redundant network overhead that could
2.5

Authentication Type

The IEEE 802.11b standard describes a simple authentication method between the wireless stations and
AP. Three authentication modes are defined: Auto, Open and Shared.
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 the WEP encryption and specify a 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
stations.
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 stations 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 stations 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.
2-6
negatively affect the throughput performance.
Wireless Station Mode Configuration