What Is Preamble Type; What Is Ssid Broadcast; What Is Wi-Fi Protected Access (Wpa) - IOGear GWU637 User Manual

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USER'S MANUAL OF WLAN BROADBAND ROUTER

Beacon Interval represents the amount of time between beacon transmissions. Before a

station enters power save mode, the station needs the beacon interval to know when to

wake up to receive the beacon (and learn whether there are buffered frames at the access

point).

4.13 What is Preamble Type?

There are two preamble types defined in IEEE 802.11 specification. A long preamble

basically gives the decoder more time to process the preamble. All 802.11 devices

support a long preamble. The short preamble is designed to improve efficiency (for

example, for VoIP systems). The difference between the two is in the Synchronization

field. The long preamble is 128 bits, and the short is 56 bits.

Broadcast of SSID is done in access points by the beacon. This announces your access

point (including various bits of information about it) to the wireless world around it. By

disabling that feature, the SSID configured in the client must match the SSID of the

access point.

Some wireless devices don't work properly if SSID isn't broadcast (for example the

D-link DWL-120 USB 802.11b adapter). Generally if your client hardware supports

operation with SSID disabled, it's not a bad idea to run that way to enhance network

security. However it's no replacement for WEP, MAC filtering or other protections.

Wi-Fi's original security mechanism, Wired Equivalent Privacy (WEP), has been

viewed as insufficient for securing confidential business communications. A longer-term

solution, the IEEE 802.11i standard, is under development. However, since the IEEE

802.11i standard is not expected to be published until the end of 2003, several members

of the WI-Fi Alliance teamed up with members of the IEEE 802.11i task group to

develop a significant near-term enhancement to Wi-Fi security. Together, this team

developed Wi-Fi Protected Access.

To upgrade a WLAN network to support WPA, Access Points will require a WPA

software upgrade. Clients will require a software upgrade for the network interface card,

and possibly a software update for the operating system. For enterprise networks, an

authentication server, typically one that supports RADIUS and the selected EAP

authentication protocol, will be added to the network.

Version: 1.0

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