15
Annex
WIFI SIP terminal for network requirements and
recommendations
Voice quality directly is affected by all three QoS quality
factors: loss, latency, and jitter.
The following list summarizes the key QoS requirements and
recommendations for voice (bearer traffic):
•
Voice traffic should be marked to DSCP EF per the
QoS Baseline and RFC 3246.
•
Loss should be no more than 1 percent.
•
One-way latency (mouth to ear) should be no more
than 150 ms.
•
Average one-way jitter should be targeted at less
than 30 ms.
•
A range of 21 to 320 kbps of guaranteed priority
bandwidth is required per call (depending on the
sampling rate, the VoIP codec, and Layer 2 media
overhead).
Limitations and Factors Affecting Throughput
First and foremost, throughput to the Internet is capped by the
ISP and devices upstream of the APs. Also, 802.11 is a
shared medium and is limited by other devices connected to
the wireless. Therefore throughput should always be
considered aggregate throughput. Interference (radio,
physical, electrical) and the distance from client device to the
Access Point are two major factors that have a negative
impact on observed maximum throughput. Physical obstacles,
other wireless networks and even everyday household
