Chapter 6 Wireless Lan Screens; Wireless Lan Overview; Wireless Lan Basics - ZyXEL Communications ZyWall 10 User Manual

This chapter discusses how to configure Wireless LAN on the ZyWALL 10W, 30W and 100 models.
6.1

Wireless LAN Overview

This section introduces the wireless LAN (WLAN) and some basic scenarios.
6.1.1 Additional Installation Requirements for Using 802.1x
A computer with an IEEE 802.11b wireless LAN card.
A computer equipped with a web browser (with JavaScript enabled) and/or Telnet.
A wireless client computer must be running IEEE 802.1x-compliant software. Currently, this is
offered in Windows XP.
An optional network RADIUS server for remote user authentication and accounting.
6.2

Wireless LAN Basics

This section provides background information on WLAN.
6.2.1 Channel
IEEE 802.11b wireless devices use ranges of radio frequencies called channels. Choose the radio channel
depending on your geographical area. Adjacent Access Points (APs) should use different channels to reduce
crosstalk. Crosstalk occurs when radio signals from access points overlap and cause interference that
degrades performance.
6.2.2 ESS ID
Extended Service Set (ESS) is defined as one or more APs acting as a bridge between a wired LAN and the
associated wireless clients. The ESS ID is a unique ID given to the APs and the wireless clients that
participate in the same wireless network. You can think of the ESS ID as being similar to a workgroup name
in a Microsoft network.
6.2.3 RTS/CTS
A hidden node occurs when two stations are within range of the same access point, but are not within range
of each other. The following figure illustrates a hidden node. Both stations (STA) are within range of the
Wireless LAN Screens
ZyWALL 10~100 Series Internet Security Gateway
Wireless LAN Screens
Chapter 6
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