MOS - Revision history

Marc St-Onge: Corrected some spelling and sentence structure.

2018-07-26T14:16:45Z

Corrected some spelling and sentence structure.

Luc Morissette: Added links

2018-05-31T15:48:06Z

Added links

Real Blanchet: MOS ingress-egress

2018-01-17T16:31:09Z

MOS ingress-egress

Real Blanchet: Work in progress

2018-01-17T15:33:28Z

Work in progress

New page

Mean Opinion Score, more commonly known as MOS, is a voice call quality metric range from 5 (excellent) to 1 (bad). It is a subjective method of quality assessment.

== TelcoBridges and MOS ==

[[Toolpack]] uses a well known model to evaluate a MOS value based on metric of the call. There is 3 factors that significantly impact the call quality: latency, packet loss and jitter of RTP packets. With these values with calculate a R-value that ranges from 1 to 100 where the higher means better. Finally the MOS is calculated using this formula.

MOS = 1 + 0.035R + ((R - 60) * (100 – R) * 0.000007R)

=== TelcoBridges' MOS Implementation ===
On the MOS calculated from the R-value, there is no notion of codec. We decided to apply a ratio in relation to the codec ideal MOS.
An illustration is provided below:

[[Image:mos_codec_conversion.jpg| ]]<br>

Network quality
TelcoBridges' MOS implementation adds an other concept over the standard MOS. The network quality gives a fast way to identify a bad network condition. The MOS is useful when comparing calls for the same [[NAP]] or on the same network but if you are using several codecs. The MOS value might be misleading to detect network problems.

A perfect network (no packet loss, no latency) using G.723 will have a MOS of 3.6. This represents a network quality of 100%. The only way to improve the situation will be to use an other codec.

A G.711 call with a MOS of 3.7 reprensents a network quality of 86%. With these values, you know there is something that can be improve with the network.

@@ Line 1: / Line 1: @@
-Mean Opinion Score, more commonly known as MOS, is a voice call quality metric range from 5 (excellent) to 1 (bad). It is a subjective method of quality assessment.
+Mean Opinion Score, more commonly known as MOS, is a voice call quality metric that ranges from 5 (excellent) to 1 (bad). It is a subjective method of quality assessment.
 == TelcoBridges and MOS ==
-[[Toolpack]] uses a well known model to evaluate a MOS value based on metric of the call. There is 3 factors that significantly impact the call quality: latency, packet loss and jitter of RTP packets. With these values with calculate a R-value that ranges from 1 to 100 where the higher means better. Finally the MOS is calculated using this formula.
+[[Toolpack]] uses a well-known model to evaluate a MOS value based on collected statistics for a call. There are 3 factors that significantly impact the call quality: latency, packet loss and jitter of RTP packets. Using these statistics, we calculate an R-value that ranges from 1 to 100 where a higher number is better. Finally the MOS is calculated using this formula.
@@ Line 11: / Line 11: @@
 === TelcoBridges' MOS Implementation ===
-On the MOS calculated from the R-value, there is no notion of codec. We decided to apply a ratio in relation to the codec ideal MOS.
+For the MOS calculated from the R-value, there is no notion of codec. We decided to apply a ratio in relation to the codec's ideal MOS.
-An illustration is provided below:
+See the table below:
@@ Line 19: / Line 19: @@
 ==== Network quality ====
-TelcoBridges' MOS implementation adds an other concept over the standard MOS. The network quality gives a fast way to identify a bad network condition. The MOS is useful when comparing calls for the same [[NAP]] or on the same network but if you are using several codecs. The MOS value might be misleading to detect network problems.
+TelcoBridges' MOS implementation adds another concept over the standard MOS: Network quality. The network quality parameter provides a fast way to identify a bad network condition. The MOS is useful when comparing calls for the same [[NAP]] or for the same network. But if you are using several codecs, the MOS value might be misleading to detect network problems.
 *'''Examples:'''
-**A perfect network (no packet loss, no latency) using G.723 will have a MOS of 3.6. This represents a network quality of 100%. The only way to improve the situation will be to use an other codec.
+**A perfect network (i.e. no packet loss, no latency) using G.723 will have a MOS of 3.6. This is relatively low, but it represents a network quality of 100%. The only way to improve the MOS will be to use a higher quality codec.
-**A G.711 call with a MOS of 3.7 represents a network quality of 86%. With these values, you know there is something that can be improved in the network.
+**On the other hand, a G.711 call with a MOS of 3.7 represents a network quality of 86%. This rather low and based on these values, you know there is something that can be improved in the network.
 ==== Ingress-Egress ====
-There is 2 MOS values calculated per leg of a call. The ingress value is using RTP reception statistics and the egress value is using RTCP statistics from the peer. Both values have the network quality value associated.
+There are 2 MOS values calculated per call leg. The ingress value is using RTP reception statistics and the egress value is using RTCP statistics received from the peer. Using these statistics, w can calculate MOS and network quality for the ingress and egress directions.
-When using [[Call_Trace|Call Trace]] the lowest value between the ingress and the egress MOS is visible in the resume.
+When using [[Call_Trace|Call Trace]], the lowest value between ingress and egress MOS and network quality are displayed.
 [[Category:Glossary]]

← Older revision		Revision as of 15:48, 31 May 2018
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	[[Category:Glossary]]		[[Category:Glossary]]
	[[Category:Sbc_Features]]		[[Category:Sbc_Features]]
		+
		+	==Related subject==
		+	*[[Toolpack:RADIUS_CDR_attributes_D\|MOS scores in CDRs]]
		+	**[[Call_statistics_format_C\|Statistics in the CDRs ]]
		+	*[[Routing_script_tutorial:Mini_Development_Guide#Nap_status\|MOS in routing scripts]]