[Freeswitch-users] [Freeswitch-dev] VMWare voice quality

Remko Kloosterman R.Kloosterman at mtel.nl
Thu Jan 15 14:02:53 PST 2009

Lot's of experience and suggestions here. Thanks.

I believe it should be theoretically possible to have blip-free RTP
streaming through the appliance. Most windows ethernet drivers allow for
QoS packet scheduling. If the VMware network bridge driver honors this
and syncs the buffers at 20ms frames (or whatever frame size applies)
you should be able to schale up a bit and maintain low jitter. 

Anyone knows how the VMware network bridge exactly works?

-----Oorspronkelijk bericht-----
Van: freeswitch-users-bounces at lists.freeswitch.org
[mailto:freeswitch-users-bounces at lists.freeswitch.org] Namens Gregory
Verzonden: donderdag 15 januari 2009 21:37
Aan: freeswitch-users at lists.freeswitch.org
Onderwerp: Re: [Freeswitch-users] [Freeswitch-dev] VMWare voice quality

> To the contrary, we have had quite good results in virtualized 
> environments and you don't really need timing that is that accurate to

> make it work.

If you don't handle RTP, I'm sure it is amazing. However, if you have to
do voicemail, stream audio from the server or do any kind of actual
time/latency/jitter sensitive processing, I don't care how much you tune
your hypervisor, it's never going to scale.

> We work quite well on amazon EC2 for example.  There are 2 issues I 
> know about with vmware, 1 is you need to set a setting on the host to 
> extend somewhat sane clocks being available, the second is I have seen

> issues with the bridged network adapter actually doubling up all 
> packets causing very strange issues, I suggest not using bridged 
> networking if you experience this.

I've not seen this behavior on Vmware ESX 3.5u2. Maybe an issue on
Vmware Server or Workstation?

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