Wireless Lan Coverage; Channel; Introduction To Wpa; Wep Encryption - ZyXEL Communications ZYAIR G-4100 User Manual

Table 21-2 IEEE 802.11g Data Rates and Modulation

DATA RATE (MBPS)
6/9/12/18/24/36/48/54
The ZyAIR may be prone to RF (Radio Frequency) interference
from other 2.4 GHz devices such as microwave ovens, wireless
phones, Bluetooth enabled devices, and other wireless LANs.

21.2.2 Wireless LAN Coverage

The following table shows the ZyAIR's coverage (in meters) using the included antennas. The
distance may differ depending on the network environment.

21.2.3 Channel

A channel is the radio frequency(ies) used by IEEE 802.11g wireless devices. Channels available
depend on your geographical area. You may have a choice of channels (for your region) so you should
use a different channel than an adjacent AP (access point) to reduce interference. Interference occurs
when radio signals from different access points overlap causing interference and degrading
performance.
Adjacent channels partially overlap however. To avoid interference due to overlap, your AP should be
on a channel at least five channels away from a channel that an adjacent AP is using. For example, if
your region has 11 channels and an adjacent AP is using channel 1, then you need to select a channel
between 6 and 11.

21.2.4 Introduction to WPA

Wi-Fi Protected Access (WPA) is a subset of the IEEE 802.11i standard. Key differences between
WPA and WEP are user authentication and improved data encryption. WPA applies IEEE 802.1x and
Extensible Authentication Protocol (EAP) to authenticate wireless clients using an external RADIUS
database. You can't use the ZyAIR's Local User Database for WPA authentication purposes since the
Local User Database uses EAP-MD5, which cannot be used to generate keys.
WPA improves data encryption by using Temporal Key Integrity Protocol (TKIP), Message Integrity
Check (MIC) and IEEE 802.1x. Temporal Key Integrity Protocol (TKIP) uses 128-bit keys that are
dynamically generated and distributed by the authentication server. It includes a per-packet key
mixing function, a Message Integrity Check (MIC) named Michael, an extended initialization vector
(IV) with sequencing rules, and a re-keying mechanism.

21.2.5 WEP Encryption

WEP (Wired Equivalent Privacy) encrypts data frames before transmitting over the wireless network.
WEP encryption scrambles the data transmitted between the wireless stations and the access points to
keep network communications private. It encrypts unicast and multicast communications in a network.
Wireless LAN
OFDM (Orthogonal Frequency Division Multiplexing)

Table 21-3 Wireless LAN Coverage

≤11 Mbps
Indoor 50 m
Outdoor
200 m
ZyAIR G-4100 User's Guide
MODULATION
≤ 5.5 Mbps
80 m
300 m
21-3