ZyXEL Communications HS100/HS100W manual Preamble Type, WEP Authentication Steps

HomeSafe User’s Guide

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.

7-4 Wireless Security