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 From:  "John Voigt" <megeek at jvoigt dot com>
 To:  "Adam Nellemann" <adam at nellemann dot nu>
 Cc:  <m0n0wall at lists dot m0n0 dot ch>
 Subject:  Re: [m0n0wall] QoS for VoIP
 Date:  Sat, 26 Jun 2004 13:20:22 -0400
----- Original Message ----- 
From: "Adam Nellemann" <adam at nellemann dot nu>
>
> Yes, but what about when a queue on some other device (router, modem,
> whatever) becomes saturated (which can happen if the shaper pipe is
> larger than the actual bandwidth)? Won't such a situation (in some
> circumstances, such as when it is the incomming traffic that is
> saturated) prevent m0n0wall from shaping properly, as it will then be
> that other, saturated, device that is "responsible" for throtling the
> bandwidth (such as by dropping packets), and since that device doesn't
> "honor" the m0n0wall shaper rule/pipe/queue setup, shaping will be
> arbitrary (ie. like without the m0n0wall shaper enabled) until the
> device is again un-saturated, and the m0n0wall shaper pipes and queues
> are once again the only "bottleneck".
>
> I might still be missing something, but unless there is more to it
> than the part about being able to use the whole bandwidth, I would
> personally still choose to forgo those 1-5% of my bandwidth, if it
> means the shaper will work better (especially since the above problem
> typically occur when shaping is most important, as in when the line is
> near saturation). Also, I get the impression that one always tend to
> loose a little bandwidth when using a traffic shaper (or was that just
> the latency getting somewhat higher?)
>
>
> Adam.
>

You can always run into bottlenecks on the other side of monowall - it is
the internet after all.  Shaping is ALWAYS arbitrary when it comes to that
part.  On the inside (the side I control) I don't see a problem.

Obviously, if you create more pipes than you have bandwidth then your
scenario is valid.  With only 1 pipe (in each direction) and multiple
weighted queues I don't see how you're going to run into a problem.

In my network I only have 2 pipes - 1 in and 1 out - each larger that the
available bandwidth.

I have 3 queues in each pipe (total of 6):

1 for "priority" traffic (so my Vonage phone line works right.)
1 for "bulk" traffic (I have a replayTV unit that sends very large files)
1 for everything else

I don't want the RTV unit killing my normal browsing and I don't want
anything messing up my phone calls.

My setup works exactly as I wanted.  Last night I had a RTV transfer
running, my kids were on the phone and I was browsing away and everyone was
happy.

Maybe I just got lucky but I'm pretty sure things are working the way I
designed it.

Now if my ISP (comcast) gets saturated, my rules aren't gonna help at all.

Maybe I misunderstood your question or the point you were making.  I just
don't see any reason to not use that 1-5% as I'm struggling to figure out
what we're saving it for.

John/