[Asterisk-Users] How to learn or teach VoIP QoE

Mojo with Horan & Company, LLC mojo at horanappraisals.com
Tue Sep 19 09:56:22 MST 2006


I've heard a MOS of 4.4 is ulaw/alaw, presumably like a local exchange 
call through the pstn.

testyourvoip.com tells me that the highest score available with G.729 is 
4.2, which is pretty darn close to 4.4.

I don't know why I think this (or why I've heard it (or if it's right)) 
but I think gsm is 3.8?  Maybe someone can confirm or disconfirm this. 
This kinda seems like the codec my long distance calls go out on but I'm 
not really sure.

http://www.testyourvoip.com/results.html?id=071GM0&result=0
(one of my more POOR results) approximates about 2.75 for 'tin cans and 
string', 3.2 for a crummy cell phone call, about 3.9 for a decent cell 
call, 4.4 or so for 'like calling next door', and the mystical 5.0 for 
'better than being there'.

I wonder if 16kHz wideband codecs would bring our voice-carrying 
experiences into the 5.0 range?

Moj



Olivier wrote:
> Hi,
> 
> How would you best learn VoIP Quality of Experience ?
> 
> Before diving into packet loss and jitter, I would like to know what a 
> toll-quality call is, what a rated 3.5 MOS call is like.
> I'm wondering how I should proceed.
> 
> Shall I :
> - get pre-recorded sound files somewhere and simply stream them to a MOS 
> enabled softphone (Counterpath sells eye-beam which includes a telchemy 
> MOS rating module),
> - or shall I install some network impairment software, generate VoIP 
> trafic and tweak myself jitter and other parameters so that I can 
> associate network measures to call quality ?
> 
> I've never heard of any sound files library aimed to learn what the 
> impact of packet is like for end user experience.
> I've seen here and there network simulators (some of them free of 
> charge) but it seems tricky to tune them to VoIP (is a 10% packet loss 
> realistic or not ?).
> 
> To make myself perfectly clear, my ultimate goal is to better undestand 
> users testimonies when they warn me about poor quality phone calls.
> 
> Regards
> !DSPAM:500,450f2da465292693510148!
> 
> 
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-- 
Mojo <mojo at horanappraisals.com>
Office Manager, Horan & Company, LLC
(907) 747-6666 x112


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