Vodavi ip-7008d 用户指南
Telenium
IP
Tech Specs
80
December, 2005
Vodavi Telenium
IP
Product Guide
mobility ▪ presence ▪ collaboration ▪ convergence
Quality of Service Requirements
In order to assure good packet voice quality, the network must be engineered to provide
prioritization for voice packets, and must have enough available bandwidth to carry the traffic
load without excessive delay, jitter, or packet loss. Note that when the network used is the
Internet, quality of service can not be assured, due to the lack of control available for Internet
traffic.
Network and Bandwidth Requirements
The amount of bandwidth taken by VoIP calls depends on the amount of conversation passing
between the calling parties. The figures below represent a constant packet data stream from
between the calling parties. The figures below represent a constant packet data stream from
constant audio on both sides:
Number of simultaneous calls:
2 4 6 8
348.8 697.6 1046.4 1395.2
(G.711)
87.48 174.96 262.44 349.92
(G.723.1)
required bandwidth in Kbps
These figures only represent the amount of bandwidth taken up by VoIP calls—they are not
recommended bandwidth minimums. Factors that can add to overhead, increasing bandwidth
consumption include:
- VPN – adds overhead and latency due to encryption and tunneling
- IPSEC –can increase latency due to encryption
- Older equipment – can add latency by requiring that frames be broken into smaller units
before transmission to the next point on the route