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 From:  Mark Ryan <markryan at cfl dot rr dot com>
 To:  Chris Hoy Poy <chrishp at dugeo dot com>
 Cc:  m0n0wall at lists dot m0n0 dot ch
 Subject:  Re: [m0n0wall] traffic shaper borrowing
 Date:  Tue, 24 Oct 2006 21:55:25 -0400
Chris Hoy Poy wrote:
> no, its *extremely* effective at smoothing the traffic when you have it set 
> near the right bandwidth. Dont forget that the traffic shaper can only have 
> limited effect on incoming traffic anyway, as those packets are sent from the 
> upstream provider.
>
> I had a few problems with ADSL routers that had low buffers, and normal 
> traffic to them would flood them so much they'd disconnect from the net (so 
> the net connection would see-saw under load). The traffic shaper effectively 
> stopped this, and under load the traffic would be nicely smoothed (and still 
> responsive, so the acks/nacks were getting thru in a timely fashion etc).
>
> //chris
>
> On Wednesday 25 October 2006 09:00, Mark Ryan wrote:
>   
>> Chris Hoy Poy wrote:
>>     
>>> hello again ;)
>>>
>>> You've got pipes and queues.
>>>
>>> my understanding is this:
>>>
>>>  Queues represent possible slices of a pipe. The shaper will try to allow
>>> each queue its *minimum* % bandwidth of a pipe, but the queue is allowed
>>> to use all of the pipe if its available.
>>>
>>> But pipes represent a hard limit, to my knowledge, and wont borrow from
>>> other pipes. You need to do that allocation at the queue level.
>>>
>>> Rules then allocate actual traffic to each queue.
>>>
>>> so looking at your question again : if FTP is in the low priority queue
>>> and everything else is in the high priority queue, then FTP will use the
>>> maximum pipe speed, but will drop back down to its minimum when something
>>> else happens.
>>>
>>> Note the one "semi" issue I have seen is where you allocate a pipe to be
>>> less then the bandwidth you have available - it seems to use a bucket
>>> system to allocate the pipe, so if you allocate a really small pipe (like
>>> 512kbit) and you actually have 2mbit of bandwidth there, the pipe will
>>> flood the bandwidth for 1/4 of the time available and the actual usage
>>> will be very jagged. That may not apply, but I've done it a few times
>>> without thinking and found the behaviour (though it makes sense when I
>>> think about it) at the time was a bit bizarre. There might be some way to
>>> change the interval that the traffic shaper uses? It seems to be set at
>>> like 5 or 10 seconds. Having smaller intervals would make the flow a bit
>>> smoother, I assume.
>>>
>>> does that make sense? ;)
>>>
>>> On Tuesday 24 October 2006 09:44, Mark Ryan wrote:
>>>       
>>>> I've been evaluating whether the m0n0wall traffic shaper will work for
>>>> me and I have to say wow!  It seems very nice.
>>>>
>>>> I do have 1 question:
>>>>
>>>> Does the traffic shaper use borrowing?  Such as if i have 2 upload ques,
>>>> ftp assigned to low priority que and everything else assigned to high
>>>> prio que.  Will the ftp consume the maximum available pipe speed until
>>>> something in the high prio ques needs it, then i would assume the ftp
>>>> traffic would slow down until the bw is available again?
>>>>
>>>> Sorry for the cryptic question there.
>>>>
>>>> Mark
>>>>
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>>>>         
>> Yes, makes sense.  That jagged use of bw bothers me though.  Does that
>> happen if you set the pipe close to the bw available?
>>
>> Thanks for the explanation!
>>
>> Mark
>>     
>
>   
Excellent.  I hope to be using it on a 10mbit/1mbit Cable connection.  I 
am just trying to justify to myself that spending $215 on the WRAP box 
is a good deal.  :)  I have an IPCOP box that does really well right now 
but im tired of the noise and heat and the failing fans and harddrives.  
In 4 years ive lost 3 fans and 1 hardrive.  Plus the power consumption 
of a machine sitting idle all the time while routing isnt very attractive.

Once I convince myself to buy it, im sure I will enjoy it.

Mark