Traffic Shape or Rate Limit

John Kristoff jtk at depaul.edu
Tue Oct 2 18:43:28 UTC 2001


"Christopher J. Wolff" wrote:
> I'm wondering what the list's opinions are on Traffic-Shaping vs. Rate-Limit
> for DIA customers (Frac DS3, for example).  From what I've read, Traffic
> Shaping is a better option since it doesn't drop packets.  Just curious as
> to what the opinions are.

Traffic shaping may drop less packets, but it can't not drop packets if
offered load eventually fills the buffers.  The choice of which to use
is probably a trade-off and the benefits of each depend on the
implementation.  If you're looking for simple, strict rate-limiting may
be the way to go.  The customer (or even you) might try AQM mechanisms
to help deal with congestion if that is a big concern.

Traffic shaping may give the customer some breathing room at the expense
of some latency during short periods of congestion.  You could get real
cute with traffic shaping by applying policies to different types of
traffic, but this is probably something the customer would want control
over.

My preference would be to be to setup strict rate limits so it looks
like a simple single speed pipe.

John



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