tinc and voip

[Perry Couprie]

Hi Ramses,

Thanks for the tip, we wil try that :-)

Perry


On 08/06/2010 12:35 PM, Ramses II wrote:
> Perry, with what codec are you working?
>
> Try to work with gsm codec or g729 and try again.
>
>
> Best regards,
>
> Ramses
>
> ________________________________________
> De: tinc-bounces at tinc-vpn.org [mailto:tinc-bounces at tinc-vpn.org] En nombre
> de Perry Couprie
> Enviado el: viernes, 06 de agosto de 2010 11:54
> Para: tinc at tinc-vpn.org
> Asunto: Re: tinc and voip
>
> Thanks for your help :-)
>
> Here some results.
>
> We did a test with 3 voip phones, the extra traffic was about 600kbits/s.
> Then with 2 phones en 1 phone.
>
> The result was that each phone adds 200kbits of tinc traffic.
>
> Then we measured the other interface on wich the phones where connected.
>
> We found that the traffic was 160kbits/s for each phone, sothat the overhead
> added by tinc is 25%.
>
> Then we increased compression to 11, at wich we gain no extra compression,
> but then we had sounds problems.
> Which is logical because voip is already compressed data.
>
> After that we switched of the compression complety and stil the same result.
> But a lower system load on the computers.
>
> The final conclusion, the overhead that tinc adds is arround 25%.
>
> I hope that these results are to some use to you.
>
> Greeting from Amsterdam, Perry
>
> ps: Tinc is super, keep up the good work ;-)
>
>
> On 08/04/2010 11:08 PM, Guus Sliepen wrote:
> On Wed, Aug 04, 2010 at 10:44:36PM +0200, Perry Couprie wrote:
>
>
> I want to use tinc for voip phones.
>
> How can i measure the overhead ?
> Compared to a direct connection ?
>
> How can i reduce overhead when tunneling voip over tinc ?
>
>
> You can use tcpdump to see what packets are sent on an interface and how big
> they are. If you want to know latency, just use the ping command.
>
> Tinc will typically add one or a few milliseconds to the latency, and add
> around 80 bytes to each packet. You can decrease the size overhead slightly
> by
> changing the Cipher to something that can handle partial blocks, like
> blowfish-ofb for example. This will save you 4.5 bytes on average. You can
> also
> disable the Digest, this will save you another 4 bytes. So it is probably
> not
> worth it.
>
> Although in principle tinc adds only a millisecond or so to latency, it is a
> user-space program, and the operating system's scheduler can add more
> latency if
> other programs are running at the same time. So jitter is increased. You can
> minimise that by running tinc at a higher priority level (with the
> ProcessPriority option), or on Linux, you could in principle run it as a
> real-time process with the chrt command from the util-linux package.
>
>
>
>
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