Quality of Service (QoS) VoIP , , , . , , QoS .
VoIP (voice traffic) (data traffic). Quality of Service .
, VoIP - (VoIP , ), - . , . (delay), , . , (, ) .
, , . ( ) , , , , . Quality of Service. QoS, , , , . QoS .

QoS, , . :
- (Lack of bandwidth) .
- (Delay) - . :
- (Fixed delay) , . , , . QoS .
- (Variable delay) , . , , , . .
- (Jitter) . , 100 , 110 . 10 .
- (Packet loss) - .
, , , .
QoS , . , . , , QoS , , .
QoS , . QoS , .
, , QoS. , . , . , .
, :
- (End-to-end delay) : 150
- : 30
- : 1%
, . , ( ).
, QoS . :
- (Mission-critical applications) .
- (Transactional applications) . , ID .
- (Best-effort applications) . , FTP.
- (Scavenger applications) , , . , p2p BitTorrent
QoS.