ZyXEL Communications Parental Control Gateway HS100/HS100W - Manual (Page 97)

HomeSafe User’s Guide
7-4 Wireless Security
Figure 7-3 WEP Authentication Steps
Open system authentication involves an unencrypted two-message procedure. A wireless station
sends an open system authentication request to the AP, which will then automatically accept and
connect the wireless station to the network. In effect, open system is not authentication at all as
any station can gain access to the network.
Shared key authentication involves a four-message procedure. A wireless station sends a shared
key authentication request to the AP, which will then reply with a challenge text message. The
wireless station must then use the AP’s default WEP key to encrypt the challenge text and return
it to the AP, which attempts to decrypt the message using the AP’s default WEP key. If the
decrypted message matches the challenge text, the wireless station is authenticated.
When your HomeSafe's authentication method is set to open system, it will only accept open
system authentication requests. The same is true for shared key authentication. However, when it
is set to auto authentication, the HomeSafe will accept either type of authentication request and
the HomeSafe will fall back to use open authentication if the shared key does not match.
7.3.3 Preamble Type
A preamble is used to synchronize the transmission timing in your wireless network. There are
two preamble modes: Long and Short.
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 if you have a ‘noisy’ network or are unsure of what preamble mode your 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
HomeSafe and the wireless stations and to provide more reliable communication in ‘noisy’
networks.