[asterisk-users] Extract a MOS value from Asterisk CDR

[John Todd]

Thank you for the interesting links on MOS values and calculations!   
It seems that many (most?) of the values that are used to construct R  
and MOS could be obtained from the data that exists within the  
dialplan, at least as far as the visible RTP path is concerned.   Or  
is there data missing in the current RTCP statistics that would be  
required to make correct R/MOS value estimates?  (If so, then that's  
on-topic for asterisk-dev, otherwise this should be moved to asterisk- 
users...)

Here is the data that I think is already visible:

  - codec choices
  - round-trip delay to RTP endpoint
  - packet loss
  - jitter

I think it is too complex to determine "Irecency", "A" or packet loss  
bursts unless there is significant additional code added to Asterisk  
to capture more granular time-slices of data on each call.  I also  
think that mid-call codec changes should not be considered due to  
complexity.  Currently, I think this is un-necessary since most people  
don't even seem to compute MOS to start with.

So in your examination you may come up with a script or dialplan that  
creates a synthetic R or MOS value - could you post it to a blog, or  
if it is very short, to the asterisk-users mailing list?  I think this  
would be worthwhile.

JT



On Apr 1, 2009, at 2:57 PM, Mindaugas Kezys wrote:

> Sorry for replying for the second time, but this issue is  
> interesting for me
> also.
>
> I found such link: http://www.nessoft.com/kb/50
>
> And this: http://www.jdsu.com/product-literature/voipstats_an_acc_tm_ae.pdf
>
>
> Regards,
> Mindaugas Kezys
> http://www.kolmisoft.com
> VoIP Billing and Routing Solutions
>
>
> -----Original Message-----
> From: asterisk-users-bounces at lists.digium.com
> [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Marc  
> Leurent
> Sent: 2009 m. balandžio 1 d. 18:15
> To: Asterisk Users Mailing List - Non-Commercial Discussion
> Subject: [asterisk-users] Extract a MOS value from Asterisk CDR
>
> Hello all,
> I'm tring to retrieve a formula to calculate a MOS value from  
> Asterisk RTCP
> stats...
> Have you got any idea how to do it?
> Thanks
>
> I'm reading all G.107 ITU docs to retrieve something...
>
> I'm saving the SIP RTCP stats with:
>
> [macro-hangupcall]
> exten => s,1,Set(CDR(userfield)=${CHANNEL(rtpqos|audio|all)})
> exten => s,n,ResetCDR(vw)
> exten => s,n,NoCDR()
>
> So I retrieve these values in my MySQL CDR table in order to  
> calculate a MOS
>
> value:
> "ssrc 
> = 
> 592614191;themssrc=0;lp=1;rxjitter=0.000000;rxcount=0;txjitter=0.00000
> 0;txcount=20734;rlp=0;rtt=0.094000"
> codec used: g711a
>
>
> -- 
> -- --
> Marc LEURENT
> lftsy at leurent.eu
>
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---
John Todd                       email:jtodd at digium.com
Digium, Inc. | Asterisk Open Source Community Director
445 Jan Davis Drive NW -  Huntsville AL 35806  -   USA
direct: +1-256-428-6083         http://www.digium.com/