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 From:  David W. Hess <dwhess at banishedsouls dot org>
 To:  "Bob Young" <bob at lavamail dot net>
 Cc:  <m0n0wall at lists dot m0n0 dot ch>
 Subject:  Re: [m0n0wall] VoIP voice quality surprise
 Date:  Sat, 05 Aug 2006 18:52:31 -0500
On Wed, 2 Aug 2006 23:48:45 -0400, you wrote:

>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.

This is how I had my Monowall system setup.  I used 2 outgoing and 2 incoming
queues with one pair for general traffic and the other for low latency and high
priority.

>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.

They have a setting where you can adjust which codec is used but my Vonage
connection always ends up using the high quality 96 Kbps one.

>No other data was flowing in my network.

The real test will be when your upload and download traffic is saturated.

>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.

I had the same problem at one time.  Someone should correct me if I am wrong but
my testing showed that the traffic shaper rules only apply to packets that are
incoming on the specified interface.  To shape outgoing traffic, the rule has to
be on the LAN or OPT interface.  To shape incoming traffic, the rule has to be
on the WAN interface.  In practice this means the direction field has to always
be set to "In" and the rule has to be placed on a specific interface to set the
direction.