[Freeswitch-users] KVM vs. XEN virtualization

[Stanislav Sinyagin]

Important is to send the media through two independent carriers - then you
can be sure that your clock is compared against a high quality one.
On Apr 4, 2015 12:46 PM, "Regis M" <regis.freeswitch.org at tornad.net> wrote:

> Hi,
>
> It's a very interresting test and conclusion.
>
> I will try to build a similar environnement on my freeswitch to check some
> system :)
>
> thanks
>
>
>
> 2015-04-04 2:16 GMT+02:00 Stanislav Sinyagin <ssinyagin at gmail.com>:
>
>> hi,
>>
>> Here are some test results which might be interesting:
>>
>> I've set up a test FreeSWITCH server at digitalocean (they use KVM),
>> and originated test calls to some ITSP accounts. Each call played a
>> test sound file (voice samples from ITU:
>> http://www.itu.int/net/itu-t/sigdb/genaudio/AudioForm-g.aspx?val=1000050
>> ), and on the receiving end another FreeSWITCH server was recording
>> the received session. The receiving server was on a XEN VM. Both
>> servers talked G711 to their corresponding ITSP accounts.
>>
>> Then I compared the source audio and received audio in Audacity editor.
>>
>> The tests showed that the received voice wave shifts 20ms from the
>> original sound every few seconds, randomly back and forward. This
>> skewing was always present, regardless of ITSP and time of day.
>>
>> Then I moved the sending server to a XEN VM, and the waves appeared
>> almost perfectly synchronized (there was a 5ms skew in one test, and I
>> guess it's related to transcoding buffer, as the sound was obviously
>> transcoded).
>>
>> The effect was always visible with a 30-second sample, and I also made
>> additional tests with 2-minute samples.
>>
>> It would also be interesting to test this from a VmWare VM. If someone
>> wants to run such a test, feel free to contact me directly.
>>
>>
>> cheers,
>> stan
>>
>> _________________________________________________________________________
>> Professional FreeSWITCH Consulting Services:
>> consulting at freeswitch.org
>> http://www.freeswitchsolutions.com
>>
>> Official FreeSWITCH Sites
>> http://www.freeswitch.org
>> http://confluence.freeswitch.org
>> http://www.cluecon.com
>>
>> FreeSWITCH-users mailing list
>> FreeSWITCH-users at lists.freeswitch.org
>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>> http://www.freeswitch.org
>>
>
>
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services:
> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
>
> Official FreeSWITCH Sites
> http://www.freeswitch.org
> http://confluence.freeswitch.org
> http://www.cluecon.com
>
> FreeSWITCH-users mailing list
> FreeSWITCH-users at lists.freeswitch.org
> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
> http://www.freeswitch.org
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20150404/80899b9e/attachment.html