E-Model(R value / MOS value)
R-value
The R-value is defined ITU-T and ETSI TIPOON(the E-model). The value is composed by network delay, network jitter and codec characteristics.
In the VOIP case, using a codec test stream, the R-value is a value on the perceived QoS level. I.e. an R-value of 92 is equivalent of an excellent user experience.
MOS-value
The MOS-value, Mean Opinion Score, is composed by network delay, network jitter, and codec characteristics.
In the VoIP case, using a codec test stream, the MOS value is a value on the user perceived QoSlevel. I.e. an MOS value of 4.4 is the equivalent of having “all users very satisfied” with the QoS
| R/MOS-value | |||
| R-value comment | R-value | MOS-value | MOS-value comment |
| Excellent | 90-100 | 4.34-4.5 | All user are very satisfied |
| Good | 80-90 | 4.03-4.34 | All user are satisfied |
| Fair | 70-80 | 3.60-4.03 | Some user are dissatisfied |
| Poor | 60-70 | 3.10-3.60 | Many user are dissatisfied |
| Bad | 50-70 | 2.58-3.10 | Nearly all user are dissatisfied |
Jitter buffer and Playout algorithm
The poor quality of Voice over IP can be improved by adaptive playout buffering at the receiver. This technique dynamically adapts the playout deadline to network conditions, thus minimizing both late packet loss and buffering time. A standard playout buffer strategy uses an estimate (Exponentially Weighted Moving Average) of the mean and variance of network delay to set the playout deadline. This estimation is characterized by a fixed, constant weighting factor
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Adjust Mean Time (A : Mean Time, T : RTT, α : constant < 1) Adjust Variation Time (V : Variation Time, A : Mean Time, T : RTT, β :constant < 1) RTO (RTO : Retransmission Time Over, k : constant = 4) |
Quality of Service Result
Measurement Configuration
|
Interval duration Packet rate Packet size TOS Playout model constant Playout timeout Playout timepass |
5mSec 712Kbps 70Byte 0 alpha : 1/8, beta : 1/16, K : 4 60mSec 10mSec |
Measurement Statistics
|
Request Packet loss Playout loss Loss rate (Pakcet + Playout) |
1600 0 12 0.75% |
MOS & E-Model value
|
Mean Playout time division by 2 |
29.97839mSec + etc delay (50 ~ 70mSec) |
| Codec Type | MOS | E-Model R | E-Model Ie | E-Model Id | E-Model Im |
| G.711 | 4.17929 | 84.41261 | 6.62791 | 2.15948 | 8.78739 |
| G.711 PLC | 4.31348 | 88.99016 | 2.05036 | 2.15948 | 4.20984 |
| G.723.1 5.3k | 3.58466 | 69.73749 | 21.30303 | 2.15948 | 23.46251 |
| G.723.1 6.3k | 3.74100 | 73.14895 | 17.89157 | 2.15948 | 20.05105 |
| G.726 16k | 2.59859 | 50.44912 | 40.59140 | 2.15948 | 42.75088 |
| G.726 24k | 3.33892 | 64.68568 | 26.35484 | 2.15948 | 28.51432 |
| G.726 32k | 3.88619 | 76.52537 | 14.51515 | 2.15948 | 16.67463 |
| G.726 40k | 4.07486 | 81.37385 | 9.66667 | 2.15948 | 11.82615 |
| G.728 16k | 3.73014 | 72.90538 | 18.13514 | 2.15948 | 20.29462 |
| G.729 | 3.92208 | 77.40052 | 13.40000 | 2.39948 | 15.79948 |
| G.729A | 3.87480 | 76.25122 | 14.54930 | 2.39948 | 16.94878 |
| GSM FR(6.10) | 3.29734 | 63.85766 | 27.18286 | 2.15948 | 29.34234 |
Round Trip Time Chart
Y.1541 Values
|
IPTD-MIN IPTD-MAX(99.9%) Y.1541 IPTD Y.1541 IPDV Y.1541 IPLR Y.1541 IPER |
35.79300mSec 56.49000mSec 39.58216mSec 20.69700mSec 0.00750 0.00000 |
Histogram and Gamma Distribution
Gamma Distribution values
|
Distance(Gamma function) Alpha(Gamma function) Beta(Gamma function) Trimming(Uper bound only) Trimming Mean Trimming Variation Trimming Standard deviation Arithmetic Mean Arithmetic Variation Arithmetic Standard deviation |
35.79300mSec 6.89233 0.51759 2.67891% 39.36041mSec 1.84646mSec 1.35884mSec 39.59662mSec 4.13795mSec 2.03420mSec |