Re: [xrblock] Transport of I.D-xrblock-rtcp-xr-qoe style quality datain IPFIX

[Qin Wu <[e-mail]>]

I tend to agree, thanks again for your clarification.

Regards!
-Qin
----- Original Message ----- 
From: "Michael Krüger" <[e-mail]>
To: "Qin Wu" <[e-mail]>
Cc: "Hendrik Scholz" <[e-mail]>; <[e-mail]>
Sent: Tuesday, July 24, 2012 3:08 PM
Subject: Re: [xrblock] Transport of I.D-xrblock-rtcp-xr-qoe style quality datain IPFIX


> Hi, Qin,
> 
> Am 24.07.12 05:20, schrieb Qin Wu:
>> Hi,Michael:
>> Thank for your clarification.
>> One thing I am not clear to your idea  is how to calculate MoS value or Rating value based on stream data from multiple sources?
>> Currently in QoE XR draft, we support MoS calculation per SSRC or MoS calculation per audio channel?
>> It seems you claim you can calculate MoS values based on audio data from multi-channels? 
>> Is that MoS value is the weighted mean of MoS value of each channel? If in that case, what the weight for each 
>> channel MoS calculation?
>> Maybe this is just implemenation specific issue, however I am interested to listen to that.
>> 
> Thank you for your interest.
> Of course we have not reinvented MOS. Our approach is related to ITU-T
> P.564. The audio test samples used in that standard have a minimum
> length of 8-seconds. We therefore assume that one must evaluate at least
> this period of time, to determine a reliable MOS value. What we try to
> achieve with monitoring live traffic, is to determine for every
> individual flow of a VoIP call MOS values for every 10-second segment.
> This provides us with many MOS values over the duration of an individual
> call. Most network impairments are of transient nature, so for every
> call the result will be a distribution of MOS scores falling into one of
> the 5 classes. Depending on the number of seconds in each of the
> classes, it is possible to assess how many seconds of a call have been
> with which quality on the MOS scale 1-5. If this data is available for a
> single flow, call, etc. the seconds of the 5 classes can be aggregated
> over all flows/calls performed between VoIP operators, operators and
> customers, or simply SIP-trunks. This will e.g. allow to come up with
> new SLA agreements where the agreement could possibly be that 99% of all
> VoIP minutes must be in the highest MOS class. The accuracy of this is
> pretty high, since one determines MOS values for only a few seconds of a
> call, bringing every impairment to attention via a lower MOS value for
> the segment in which the impairment occurred. No averaging over a call
> is done, so the distribution of MOS values like this, truly reflects the
> monitored quality.
> 
> Does this make sense to you as well?
> 
> Regards,
> Michael
> 
>> Regards!
>> -Qin
>> 
> 
>