[47929] in North American Network Operators' Group
Re: Network Reliability Engineering
daemon@ATHENA.MIT.EDU (Ralph Doncaster)
Sat May 18 19:22:35 2002
Date: Sat, 18 May 2002 19:23:14 -0400 (EDT)
From: Ralph Doncaster <ralph@istop.com>
To: Pete Kruckenberg <pete@kruckenberg.com>
Cc: "nanog@merit.edu" <nanog@merit.edu>
In-Reply-To: <Pine.LNX.4.33.0205181701090.32373-100000@minot.kruckenberg.com>
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Good luck. For a proper scientific analysis you'd need MTBF info on every
point of failure - i.e. the physical link, CSU/DSU, power supply, ...
As a rather non-scientific observation, a couple outages per year of 1-4
hours seems to be quite common for a single-homed T1 or faster connection,
be it from WorldCom, AT&T, Sprint...
I think the arguments in favor of dual-homing are pretty cut and
dry. Tri-homing vs dual-homing would be a much tougher benefit to
quantify.
Ralph Doncaster
principal, IStop.com
div. of Doncaster Consulting Inc.
On Sat, 18 May 2002, Pete Kruckenberg wrote:
>
> I'm looking for some good reference materials to do some
> "reliability engineering" calculations and projections.
>
> This is to justify increased redundancy, and I want to
> include quantifiable numbers based on MTBF data and other
> reliability factors, kind of a scientific justification
> instead of just the typical emotional appeal using
> analyst/vendor FUD.
>
> I'd appreciate references on how to do this in a network
> environment (what data to collect, how to collect it, how to
> analyze, etc). Also any data (or rules of thumb) on typical
> MTBFs for network events that I won't find on vendor product
> slicks (like what's the MTBF on IOS, or human-caused service
> outages of various types, etc).
>
> If someone has put together something remotely like this
> that they'd care to share, that'd be incredibly helpful.
>
> Thanks.
> Pete.
>
>
>
