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 From:  "Bob Young" <bob at lavamail dot net>
 To:  <m0n0wall at lists dot m0n0 dot ch>
 Subject:  VoIP voice quality surprise
 Date:  Wed, 2 Aug 2006 23:48:45 -0400
Hello all:


I'm in the process of learning to set up the Traffic Shaper with VoIP.


Since I want high priority for my VoIP, I figured I should have a separate
"inbound pipe" and a separate "outbound pipe" for my VoIP data (audio).  I
hope that rationale is correct.  I figured I didn't want it to be part of a
queue.  I figured separate pipes for VoIP would give the best priority.I
hope that was correct.


I was told by my VoIP company (Vonage) that my VoIP should sound good with
just 100 Kb bandwidth.  So I set up a "Pipe 3 for VoIP outbound" and "Pipe 4
for VoIP inbound".   Initially I set both to 100 Kb.  And when I talk on my
VoIP phone to my wife on my cell phone both voice directions sounded great.


No other data was flowing in my network.


And just to test to see if the BW limiting is working, I set Pipe 3
(outbound) to 25 Kbs, while I kept Pipe 4 (inbound) at 100 Kbs.  The inbound
sound sounded great, but the outbound sound (to my cell phone) was choppy
and terrible.  That is reasonable since I limited the outbound BW to 25 Kbs.
That means Pipe 3 is working.


However, I then set Pipe 4 (inbound) to 25 Kbs, and I expected to also hear
choppy, terrible sound.  But it sounded great.  That means Pipe 4 isn't
working.  I don't know why.


That means when I set the inbound BW to 25 Kbs, it must not really be at 25
Kbs, since the inbound audio is still very good.  If my Pipe 4 inbound sound
was really 25 Kbs, it would sound terrible, just like the sound produced by
Pipe 3.


Does anyone have any ideas why this is happening?   


Thank you,