Re: [ippm] Next version of the duplicate draft

Henk Uijterwaal <henk@ripe.net> Tue, 01 July 2008 14:55 UTC

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Date: Tue, 01 Jul 2008 16:55:17 +0200
From: Henk Uijterwaal <henk@ripe.net>
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To: Lars Eggert <lars.eggert@nokia.com>
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Subject: Re: [ippm] Next version of the duplicate draft
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Hi Lars,

> so what if there is no information, such as with pure TCP ACKs?
 > I wonder - since IPPM is doing metrics for IP - if we can define
 > duplication only in terms of the IP header fields?

Well, if there is nothing to distinguish two packets that were
intentionally sent over a packet that has been replicated along
the way, then one cannot use this metric.  For active measurements
between two hosts, this won't be an issues as one generates his own
packets and can  easily put something in to make them unique.
For other metrics, we haven't defined the packet format or how to
do this either.

If one wants to apply the metric for other cases (say, passive monitoring
of TCP sequences), then one will have to find something in the packets
to distinguish two packets from one packet sent twice.  I'm open to
suggestions here.

Henk

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Henk Uijterwaal                           Email: henk.uijterwaal(at)ripe.net
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