ZyXEL Communications VMG1312-B Series User Manual Download

Page: 127 / 376

Chapter 7 Wireless

VMG1312-B Series User’s Guide

127

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.

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.

Table 28

Addit ional Wireless Term s

TERM

DESCRIPTION

RTS/ CTS Threshold

I n a w ireless net work which covers a large area, wireless devices are som et im es not
awar e of each ot her ’s pr esence. 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 hr ough.

By set t ing t his value low er  t han t he default  value, t he w ireless devices m ust
som et im es get  perm ission t o send infor m at ion t o t he Device. The low er  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 hr eshold value ( see below ) , t hen
w ir eless devices never have t o get perm ission t o send infor m at ion t o t he Device.

Pream ble

A pream ble affect s t he t im ing in your w ireless net w or k. Ther e ar e t w o pr eam 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 w it h t he Device.

Aut hent icat ion

The process of verifying whet her a wireless device is allow ed t o use t he w ireless
net w ork.

Fragm ent at ion
Threshold

A sm all fragm ent at ion t hreshold is recom m ended for busy net w orks, w hile a larger
t hreshold provides fast er perform ance if t he net w ork is not very busy.

ZyXEL Communications VMG1312-B Series, User Manual

Search results

Summary of Contents for VMG1312-B Series

Reviews:

Related manuals for VMG1312-B Series

Brands by name

Popular brands