[32587] in North American Network Operators' Group
Re: Traceroute versus other performance measurement
daemon@ATHENA.MIT.EDU (Kai Schlichting)
Wed Nov 29 14:25:42 2000
Message-Id: <4.3.2.7.2.20001129141351.00dae940@127.0.0.1>
Date: Wed, 29 Nov 2000 14:21:47 -0500
To: nanog@merit.edu
From: Kai Schlichting <kai@pac-rim.net>
In-Reply-To: <20001129185450Z663-17920+7@cesium.clock.org>
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At Wednesday 01:54 PM 11/29/00, smd@clock.org wrote:
>| At the expense of using all their bandwidth ttcp should provide some
>| reasonable measure of performance under those circumstances.
>
>ttcp has the disadvantage of invariant 5-tuple, which is germane to
>this problem.
>
> Sean.
While this is moving rapidly towards a rather marginal topic, the
above struck me. And Google says for "tuple ttcp" :
http://www.cs.umn.edu/classes/Spring-1999/csci5212-nh/toc.html
Do I understand it correctly that the "invariant 5 tuple" refers to
5 non-variable aspects of this performance test, being namely:
- tcp or udp or icmp(?) protocol
- local IP address
- local protocol port or message type
- remote IP address
- remote port port or message type
E.g.: performance measurements will gravitate towards a result not
representative for the totality of all traffic, as the 5 variables
are rather fixed, or at the least fixed for the duration of the test ?
Has intelligent switching and forwarding (Layer-4 and up) started to
make such a significant impact on end-to-end performance that all
traditional performance tests must necessarily be flawed ?
(there must be a reason why my MRTG graphs of HTTP GET's to websites
are so much more consistent than icmp pings...)
--
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