nanog mailing list archives

Re: common method to count traffic volume on IX


From: Stephen Fulton <sf () lists esoteric ca>
Date: Wed, 18 Sep 2013 19:10:35 -0400

> Ding ding ding!  And that's why honest IXPs graph both, to show that
> they have no packet loss on their inter-switch links.

It depends on what is being measured. At TorIX we'll see deviations between in/out on our aggregate graph. As we combine all peer ports to form the aggregate graph, any large deviations are almost always due to peers who have reached capacity limits on their port (which is not always port speed, btw, always include their transport behind the port). Another common reason is the difference in measurement times across all ports.

http://www.torix.ca/stats.php

-- Stephen


On 18/09/2013 6:55 PM, Niels Bakker wrote:
* bicknell () ufp org (Leo Bicknell) [Wed 18 Sep 2013, 19:23 CEST]:
On Sep 17, 2013, at 3:15 PM, Niels Bakker <niels=nanog () bakker net> wrote:
I don't know of any IXP that does this.  Industry standard is as you
and others wrote before: the 5-minute counter difference on all
customer-facing ports, publishing both input and output bps and pps.
I guess MRTG is to 'blame' for these values more than anything.

Serious question, at an IXP shouldn't IN = OUT nearly perfectly?

Ding ding ding!  And that's why honest IXPs graph both, to show that
they have no packet loss on their inter-switch links.

(Or, much more likely, measurement errors due to wrong config for the
grapher)


     -- Niels.



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