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 From:  KnightMB <knightmb at knightmb dot dyndns dot org>
 To:  m0n0wall at lists dot m0n0 dot ch
 Subject:  Re: [m0n0wall] More VoIP Traffic Shaping Questions
 Date:  Sat, 04 Mar 2006 15:34:07 -0600
That's great advice, I did try that earlier and I think I may have found 
the source of the issue.

I created (2) download pipes and (2) upload pipes.  One set of pipes is 
tweaked for the maximum bandwidth I can get from my ISP which is (1.5MB 
Down/ 768 K/b Up).  The second set of download/upload pipes are set at a 
static 256 K/bs limit, both upload and download.  I assigned my 
workstation a static IP address. I assigned my VoIP gizmo another 
separate static IP address.  I create a set for rules for my VoIP gizmo, 
I give it the maximum bandwidth pipe.  I create another set of rules for 
my workstation, giving it the much more limited and slower pipes.  I run 
a speed test on my workstation and it confirms I'm limited to 256 K/bs 
both up and down.  I dial up a generic phone number that has a really 
long automated attendant menu for testing.  With the VoIP only, 
everything is nice and smooth.  If I go to cnn.com on my workstation and 
begin watching one of their news clips. At the same time, I dial that 
number again.  This time, it's terrible lag and gaps.  I check the 
m0n0wall CPU monitor, only 5% max CPU being used.  I check the m0n0wall 
traffic monitor and I can see a problem there.  While watching the 
streaming movie, it's "breaking" through the 256 K/bs barrier in spots, 
when this happens, it causes my VoIP phone to gap and lag.  I think the 
problem is in the traffic shaping feature, it doesn't seem to be able to 
"enforce" the pipe cap properly and this I believe is what causes the 
VoIP problems that show up whether it's on or off.  Since this doesn't 
involve using the packet queue, it's possible that the original setup I 
had would work properly if the pipes could hold back the bandwidth 
properly.  I haven't had a chance to test the queue system with two 
workstations to see if the weights really make a difference yet or not.  
So far it seems the traffic shaping system is broken or not working the 
way it was designed (generic 1.21 PC image) because it doesn't seem to 
always enforce the pipes, which it maybe why the VoIP packets get 
"bumped" out so to speak.

Any feedback on my findings would be greatly appreciated.


RP Smith wrote:
> The trick to traffic shaping is setting your upstream pipe size.  I 
> use the "Traffic Graph" to monitor outgoing traffic and under a 
> saturated outgoing file transfer.  I then lower the pipe size a little 
> bit at a time until the graph changes from a wavy line to a fairly 
> straight line.  The wavy line indicates you are not the one limiting 
> your outgoing traffic where as the straight line indicates you are the 
> one controlling the maximum amount of outgoing traffic.  Also, I only 
> traffic shape outgoing and not incoming traffic and my Vonage VoIP 
> adapter works flawlessly 95% of the time.
> Roy...
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