ZyXEL Communications P-660HN-F1, Руководство пользователя

Страница: 122 / 366

Chapter 6 Wireless
ADSL Series User’s Guide
122
Many types of encryption use a key to protect the information in the wireless network. The longer
the key, the stronger the encryption. Every device in the wireless network must have the same key.
6.7.3 Signal Problems
Because wireless networks are radio networks, their signals are subject to limitations of distance,
interference and absorption.
Problems with distance occur when the two radios are too far apart. Problems with interference
occur when other radio waves interrupt the data signal. Interference may come from other radio
transmissions, such as military or air traffic control communications, or from machines that are
coincidental emitters such as electric motors or microwaves. Problems with absorption occur when
physical objects (such as thick walls) are between the two radios, muffling the signal.
6.7.4 BSS
A Basic Service Set (BSS) exists when all communications between wireless stations or between a
wireless station and a wired network client go through one access point (AP).
Intra-BSS traffic is traffic between wireless stations in the BSS. When Intra-BSS traffic blocking is
disabled, wireless station A and B can access the wired network and communicate with each other.
When Intra-BSS traffic blocking is enabled, wireless station A and B can still access the wired
network but cannot communicate with each other.
Figure 39
Basic Service set
6.7.5 MBSSID
Traditionally, you need to use different APs to configure different Basic Service Sets (BSSs). As well
as the cost of buying extra APs, there is also the possibility of channel interference. The ZyXEL
Device’s MBSSID (Multiple Basic Service Set IDentifier) function allows you to use one access point
to provide several BSSs simultaneously. You can then assign varying QoS priorities and/or security
modes to different SSIDs.
Wireless devices can use different BSSIDs to associate with the same AP.