[50270] in North American Network Operators' Group
Re: PSINet/Cogent Latency
daemon@ATHENA.MIT.EDU (Joe Loiacono)
Wed Jul 24 10:56:37 2002
Date: Wed, 24 Jul 2002 10:55:43 -0400
From: Joe Loiacono <jloiacon@csc.com>
To: Matt Zimmerman <mdz@csh.rit.edu>
Cc: nanog@merit.edu
Errors-To: owner-nanog-outgoing@merit.edu
Actually RRDTool interpolates any late replys to the nearest specified
collection timepoint (e.g., every 5th minute.) It doesn't really resample.
Joe
Matt
Zimmerman To: nanog@merit.edu
<mdz cc:
@csh.rit.edu> Subject: Re: PSINet/Cogent Latency
Sent by:
owner-nanog
07/23/2002
09:46 AM
On Mon, Jul 22, 2002 at 10:50:03PM -0700, Doug Clements wrote:
> I think the problem with using rrdtool for billing purposes as described
> is that data can (and does) get lost. If your poller is a few cycles
late,
> the burstable bandwidth measured goes up when the poller catches up to
the
> interface counters. More bursting is bad for %ile (or good if you're
> selling it), and the customer won't like the fact that they're getting
> charged for artifically high measurements.
RRDtool takes into account the time at which the sample was collected, and
if it does not exactly match the expected sampling period, it is resampled
on the fly. See:
http://people.ee.ethz.ch/~oetiker/webtools/rrdtool/tutorial/rrdtutorial.html
under "Data Resampling" for more information.
RRDtool has some quirks when used for billing purposes, but it is not
guilty
of the error that you describe.
--
- mdz
