[Freeswitch-users] Audio quality issues

Guillermo Ruiz Camauer grcamauer at gmail.com
Wed Oct 23 23:28:58 MSD 2013


Here is some good data on per call real bandwidth consumption for different
codecs:

Codec BR NEB
G.711 64 Kbps 87.2 Kbps
G.729 8 Kbps 31.2 Kbps
G.723.1 6.4 Kbps 21.9 Kbps
G.723.1 5.3 Kbps 20.8 Kbps
G.726 32 Kbps 55.2 Kbps
G.726 24 Kbps 47.2 Kbps
G.728 16 Kbps 31.5 Kbps
iLBC 15 Kbps 27.7 Kbps

BR = Bit rate
NEB = Nominal Ethernet Bandwidth (one direction)


On Wed, Oct 23, 2013 at 5:33 AM, Miha <miha at softnet.si> wrote:

> Hi Steve,
>
> do you have any good preposal which switch has good performance for voip
> trafic?
>
> miha
>
> Dne 10/22/2013 3:32 PM, piše Steve Underwood:
> > Hi Grant,
> >
> > Two possibilities spring to mind:
> >
> > - If your audio is coming from a disk, can that disk keep up?
> > - How good is your ethernet switch?
> >
> > Notice in the second point I said how good, not how expensive. Many
> > switches choke on a large number of small media packets, including some
> > expensive big name products.
> >
> > Regards,
> > Steve
> >
> > On 10/22/2013 06:01 PM, Grant Bagdasarian wrote:
> >> The network shouldn’t be an issue, since we have at least 1Gbps lines.
> >> The tests stay within the network.
> >>
> >> I forgot to mention the calls are being distributed across two
> >> machines by a Kamailio instance.
> >>
> >> So for a total of 800 concurrent calls generated by Sipp, each machine
> >> has 400 active calls.
> >>
> >> CPU load reaches about 70% per machine.
> >>
> >> At this point both FS machines are virtualized, since the performance
> >> gain wasn’t that much compared to physical.
> >>
> >> The VM host shows it is using ~3/4 of its CPU resources.
> >>
> >> Htop shows that the normal priority threads(green) and the kernel
> >> threads(red) are about the same length.
> >>
> >> Also, FS is running on Ubuntu Server 12.04 x64.
> >>
> >> *From:*freeswitch-users-bounces at lists.freeswitch.org
> >> [mailto:freeswitch-users-bounces at lists.freeswitch.org] *On Behalf Of
> >> *Stanislav Sinyagin
> >> *Sent:* Tuesday, October 22, 2013 11:11 AM
> >> *To:* FreeSWITCH Users Help
> >> *Subject:* Re: [Freeswitch-users] Audio quality issues
> >>
> >> 800 calls at 64kbps is 51Mbps.
> >> Could there be a network issue, like a 100Mbps line between the
> endpoints?
> >>
> >> How heavy is your CPU load? "htop" command would be helpful in this.
> >>
> >> ------------------------------------------------------------------------
> >>
> >> *From:*Grant Bagdasarian <GB at cm.nl <mailto:GB at cm.nl>>
> >> *To:* "FreeSWITCH Users Help (freeswitch-users at lists.freeswitch.org
> >> <mailto:freeswitch-users at lists.freeswitch.org>)"
> >> <freeswitch-users at lists.freeswitch.org
> >> <mailto:freeswitch-users at lists.freeswitch.org>>
> >> *Sent:* Tuesday, October 22, 2013 10:14 AM
> >> *Subject:* [Freeswitch-users] Audio quality issues
> >>
> >> Hello,
> >>
> >> I was wondering what the maximum concurrent calls for FS before audio
> >> quality becomes an issue? I assume the specs of the machine would also
> >> affect this.
> >>
> >> We are currently running FS on a Six Core (12 Threads) Intel E5-2430
> >> CPU and get about 800 concurrent calls at 10-20 CPS. The audio quality
> >> at these rates is still fair, but we do notice some quality issue’s.
> >>
> >> Going above these numbers screws up the audio quality: choppy sound,
> >> audio drops etc. We aren’t doing any heavy media processing, just
> >> simply playing a file (G711-Alaw) which lasts about 2 minutes during
> >> the load test.
> >>
> >> These numbers are for one way audio, where Sipp doesn’t echo the RTP
> >> back. These numbers get lower once Sipp echo’s the RTP.
> >>
> >> I’ve tried FS on a physical box and also on a virtual box (ESXi 5.1),
> >> but the performance gain on physical vs virtual isn’t that much.
> >>
> >> I disabled all the modules we don’t need, like CDR’s, conferencing, etc.
> >>
> >> Are there any parameters(config files)/modules that can affect the
> >> quality of the audio stream?
> >>
> >> Regards,
> >>
> >> Grant
> >>
> >>
> >
> > _________________________________________________________________________
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> > http://www.freeswitchsolutions.com
> >
> > 
> > 
> >
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>
>
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services:
> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
>
> 
> 
>
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-- 
Guillermo Ruiz Camauer
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