ZyXEL Communications VMG1312-B Series, Руководство пользователя

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VMG1312-B Series User’s Guide
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Quality of Service (QoS)
10.1 Overview
Qualit y of Service ( QoS) refers t o bot h a net work’s abilit y t o deliver dat a wit h m inim um delay, and
t he net working m et hods used t o cont rol t he use of bandwidt h. Wit hout QoS, all t raffic dat a is
equally likely t o be dropped when t he net work is congest ed. This can cause a reduct ion in net work
perform ance and m ake t he net work inadequat e for t im e- crit ical applicat ion such as video- on-
dem and.
Configure QoS on t he Device t o group and priorit ize applicat ion t raffic and fine- t une net work
perform ance. Set t ing up QoS involves t hese st eps:
1 Configure classifiers t o sort t raffic int o different flows.
2 Assign priorit y and define act ions t o be perform ed for a classified t raffic flow.
The Device assigns each packet a priorit y and t hen queues t he packet accordingly. Packet s assigned
a high priorit y are processed m ore quickly t han t hose wit h low priorit y if t here is congest ion,
allowing t im e- sensit ive applicat ions t o flow m ore sm oot hly. Tim e- sensit ive applicat ions include bot h
t hose t hat require a low level of lat ency ( delay) and a low level of j it t er ( variat ions in delay) such as
Voice over I P ( VoI P) or I nt ernet gam ing, and t hose for which j it t er alone is a problem such as
I nt ernet radio or st ream ing video.
This chapt er cont ains inform at ion about configuring QoS and edit ing classifiers.
10.1.1 What You Can Do in this Chapter
• The Ge n e r a l screen let s you enable or disable QoS and set t he upst ream bandw idt h ( Sect ion
10.3 on page 169 ) .
• The Qu e ue Se t u p screen let s you configure QoS queue assignm ent ( Sect ion 10.4 on page 170 ) .
• The Cla ss Se t up screen let s you add, edit or delet e QoS classifiers ( Sect ion 10.5 on page 172 ) .
• The Police r Se t u p screen let s you add, edit or delet e QoS policers ( Sect ion 10.5 on page 172 ) .
• The M on it or screen let s you view t he Device's QoS- relat ed packet st at ist ics ( Sect ion 10.7 on
page 179 ) .