Thank you all for your explanations. I think I now have a better grasp of
the reasoning behind traffic shaping.

Michael

On Tue, Aug 12, 2008 at 6:48 PM, Brian Lloyd <brian dash wb6rqn at lloyd dot com> wrote:

> That's why mostly, shaping is done on the perimeter, where the LAN traffic
>> exceeds the capabilities of the WAN line.  Any shaping done should
>> feedback
>> to the internal nodes to slow down (I don't recall how traffic shaping's
>> implemented), and in essence, help control the flow through the pipe.
>>
>
> ICMP source quench was supposed to solve the problem by letting an
> intermediate system send a message to an end system and get it to throttle
> its traffic. Turned out that it ended up making the traffic level oscillate.
> (While not particularly useful, it was fun to watch.)
>
> Today the solution is to just throw packets away and let TCP cope. Most TCP
> implementations assume that lost packets are due to network congestion and
> close the transmit window. It is surprising just how well TCP will converge
> on proper throughput.
>
> (I used to design routers in a previous life.)
>
> Brian Lloyd
> Granite Bay Montessori School          9330 Sierra College Bl
> brian AT gbmontessori DOT com          Roseville, CA 95661
> +1.916.367.2131 (voice)                +1.791.912.8170 (fax)
>
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>
>
>
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>