ZyXEL Communications ZyAIR B-620, Руководство пользователя

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ZyAIR B-620 User’s Guide
5-2 Wireless LAN Security
notify all other stations to defer transmission. It will also confirm with the requesting station that the AP
has reserved it for the time frame of the requested transmission.
The RTS function will be activated if the packet size exceeds the value you set. It is highly recommended
that you set the value ranging from 0 to 2305.
Enabling the RTS Threshold causes redundant network overhead that could
negatively affect the throughput performance instead of providing a remedy.
Fragmentation Threshold
Fragmentation improves the efficiency when high traffic flows along in the wireless network.
5.1.2 Authentication Mode
The IEEE 802.11b standard describes a simple authentication method between the wireless clients 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 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.
5.1.3 Preamble Type
A preamble is a signal used to synchronize the transmission timing in your wireless network. There are two
preamble modes: Long and Short.
Long preamble mode allows more processing time for each transmitted data packet. Short preamble mode
allows less processing time for the transmitted data packets.
Using short preamble mode may minimize overhead and maximize network throughput. However, short
preamble mode is supported by IEEE 802.11b compliant wireless devices, thus wireless stations using short
preamble mode cannot communicate with wireless stations using the original IEEE 802.11 standard.
5.2 The Advanced Screen
To set the advanced features on the ZyAIR, click the Advanced tab.