<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
Thanks for your help <span class="moz-smiley-s1"><span> :-) </span></span><br>
<br>
Here some results.<br>
<br>
We did a test with 3 voip phones, the extra traffic was about
600kbits/s.<br>
Then with 2 phones en 1 phone.<br>
<br>
The result was that each phone adds 200kbits of tinc traffic.<br>
<br>
Then we measured the other interface on wich the phones where connected.<br>
<br>
We found that the traffic was 160kbits/s for each phone, sothat the
overhead added by tinc is 25%.<br>
<br>
Then we increased compression to 11, at wich we gain no extra
compression, but then we had sounds problems.<br>
Which is logical because voip is already compressed data.<br>
<br>
After that we switched of the compression complety and stil the same
result.<br>
But a lower system load on the computers.<br>
<br>
The final conclusion, the overhead that tinc adds is arround 25%.<br>
<br>
I hope that these results are to some use to you.<br>
<br>
Greeting from Amsterdam, Perry<br>
<br>
ps: Tinc is super, keep up the good work <span class="moz-smiley-s3"><span>
;-) </span></span><br>
<br>
<br>
On 08/04/2010 11:08 PM, Guus Sliepen wrote:
<blockquote cite="mid:20100804210837.GX32625@sliepen.org" type="cite">
<pre wrap="">On Wed, Aug 04, 2010 at 10:44:36PM +0200, Perry Couprie wrote:
</pre>
<blockquote type="cite">
<pre wrap="">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 ?
</pre>
</blockquote>
<pre wrap="">
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.
</pre>
<pre wrap="">
<fieldset class="mimeAttachmentHeader"></fieldset>
_______________________________________________
tinc mailing list
<a class="moz-txt-link-abbreviated" href="mailto:tinc@tinc-vpn.org">tinc@tinc-vpn.org</a>
<a class="moz-txt-link-freetext" href="http://www.tinc-vpn.org/cgi-bin/mailman/listinfo/tinc">http://www.tinc-vpn.org/cgi-bin/mailman/listinfo/tinc</a>
</pre>
</blockquote>
<br>
</body>
</html>