Additional Wireless Terms; Wireless Security Overview - ZyXEL Communications VMG1312-B Series User Manual

variet y of net works t o exist in t he sam e place wit hout int erfering wit h one anot her. When you
creat e a net work, you m ust select a channel t o use.
Since t he available unlicensed spect rum varies from one count ry t o anot her, t he num ber of
available channels also varies.

7.10.2 Additional Wireless Terms

The following t able describes som e wireless net work t erm s and acronym s used in t he Device's Web
Configurat or.
Table 28 Addit ional Wireless Term s
TERM
RTS/ CTS Threshold
Pream ble
Aut hent icat ion
Fragm ent at ion
Threshold

7.10.3 Wireless Security Overview

By t heir nat ure, radio com m unicat ions are sim ple t o int ercept . For wireless dat a net works, t his
m eans t hat anyone wit hin range of a wireless net work wit hout securit y can not only read t he dat a
passing over t he airwaves, but also j oin t he net work. Once an unaut horized person has access t o
t he net work, he or she can st eal inform at ion or int roduce m alware ( m alicious soft ware) int ended t o
com prom ise t he net work. For t hese reasons, a variet y of securit y syst em s have been developed t o
ensure t hat only aut horized people can use a wireless dat a net work, or underst and t he dat a carried
on it .
These securit y st andards do t wo t hings. First , t hey aut hent icat e. This m eans t hat only people
present ing t he right credent ials ( oft en a usernam e and password, or a " key" phrase) can access t he
net work. Second, t hey encrypt . This m eans t hat t he inform at ion sent over t he air is encoded. Only
people wit h t he code key can underst and t he inform at ion, and only people who have been
aut hent icat ed are given t he code key.
These securit y st andards vary in effect iveness. Som e can be broken, such as t he old Wired
Equivalent Prot ocol ( WEP) . Using WEP is bet t er t han using no securit y at all, but it will not keep a
det erm ined at t acker out . Ot her securit y st andards are secure in t hem selves but can be broken if a
user does not use t hem properly. For exam ple, t he WPA- PSK securit y st andard is very secure if you
use a long key which is difficult for an at t acker 's soft ware t o guess - for exam ple, a t went y- let t er
long st ring of apparent ly random num bers and let t ers - but it is not very secure if you use a short
key which is very easy t o guess - for exam ple, a t hree- let t er word from t he dict ionary.
VMG1312-B Series User's Guide
DESCRIPTION
I n a wireless net work which covers a large area, wireless devices are som et im es not
aware of each ot her 's presence. This m ay cause t hem t o send inform at ion t o t he AP
at t he sam e t im e and result in inform at ion colliding and not get t ing t hrough.
By set t ing t his value lower t han t he default value, t he wireless devices m ust
som et im es get perm ission t o send inform at ion t o t he Device. The lower t he value, t he
m ore oft en t he devices m ust get perm ission.
I f t his value is great er t han t he fragm ent at ion t hreshold value ( see below) , t hen
wireless devices never have t o get perm ission t o send inform at ion t o t he Device.
A pream ble affect s t he t im ing in your wireless net work. There are t wo pream ble
m odes: long and short . I f a device uses a different pream ble m ode t han t he Device
does, it cannot com m unicat e wit h t he Device.
The process of verifying whet her a wireless device is allowed t o use t he wireless
net work.
A sm all fragm ent at ion t hreshold is recom m ended for busy net works, while a larger
t hreshold provides fast er perform ance if t he net work is not very busy.
Chapter 7 Wireless
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