Instruction manual

Appendix – Specifications
Strata Net QSIG Over IP and IPT Bandwidth Requirements
112 Strata CTX General Description 10/04
Strata Net QSIG Over IP and IPT Bandwidth
Requirements
The amount of bandwidth required for communications over a particular IP network segment
depends on the number of voice channels supported, the anticipated call setup traffic, and how
much other data network traffic is present.
The quality of service (Excellent, Good, Fair, and Poor) provided by CTX IP QSIG channels and
IP telephones depends heavily on the LAN parameters as shown in
Table 41. This table shows the
amount of bandwidth required for each IP QSIG voice call (without data traffic) based on the
interval and the CODEC.
Table 41 Strata Net QSIG Over IP and IPT Quality of Service
IP Network Quality Parameters
Speech
Excellent: No one
perceives delay.
1
1. Ratings of Excellent, Good, Fair, Poor were based on the tester in a quiet room and the tester could not see the other call
party.
Good: Very few
people perceive
delay.
1
Fair: Some people
may perceive
delay.
1
Poor: Many people
may perceive delay.
1
IPT is usable even
with a "Poor" rating if
delay is acceptable.
Latency (Round trip delay)
2
2. When selecting router equipment, the Latency, Jitter, Packet loss and Packet error conditions above should be considered as
well as the bandwidth. Bandwidth can be calculated with the CODEC and packet size. For better results, more bandwidth may
be required, depending on the amount of overall data traffic. For more details on QoS refer to “A Handbook for Successful
VoIP Deployment: Network Testing, QoS, and More” by John Q. Walker, NetIQ Corporation on www.netiq.com.
20ms or less 50ms or less 100ms or less 200ms or less
Jitter
2
20ms or less 50ms or less 50ms or less 50ms or less
(-10 ms ~ +10ms) (-25ms ~ +25ms) (-25ms ~ +25ms) (-25ms ~ +25ms)
Packet loss
2
1×10
-3
or less 1×10
-3
or less 1×10
-3
or less 1×10
-3
or less
Packet error
2
1×10
-4
or less 1×10
-4
or less 1×10
-4
or less 1×10
-4
or less
Speech quality dependency on
CODEC parameters
Speech quality as the combination of the above network environment and the
CODEC parameters.
CODEC and
packet interval
Bandwidth per
channel (Single
direction,
control channel
included)
G.711 at 20ms
interval
Prg 250-07
Prg 152-01
115kbps
3
(Speech
88kbps)
3. Use this number to estimate the bandwidth needed for the CODEC and interval timing required to achieve an expected
Quality of Service (Excellent, Good, etc). This bandwidth includes header and control information and a 25% margin for
network traffic variances.
Excellent Good Fair Poor
G.711 at 40ms
interval
Prg 250-07
Prg 152-01
99kbps
3
(Speech
76kbps)
Excellent Good Fair Poor
G.729A at 40ms
interval
Prg 250-07
Prg 152-01
29kbps
3
(Speech
20kbps)
Good Good Fair Poor
G.729A at 80ms
interval
Prg 250-07
Prg 152-01
22kbps
3
(Speech
14kbps)
Good Fair Poor Poor