[47185] in North American Network Operators' Group
Re: The Myth of Five 9's Reliability (fwd)
daemon@ATHENA.MIT.EDU (Jim Hickstein)
Fri Apr 26 19:18:28 2002
Date: Fri, 26 Apr 2002 16:16:04 -0700
From: Jim Hickstein <jxh@jxh.com>
To: nanog@merit.edu
Message-ID: <4920000.1019862964@jxh.mirapoint.com>
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> The gap between the rhetoric of five-nines and actual
> network performance leads to the conclusion that five-nines
> may not be a realistic or even necessary goal.
In my experience, the biggest problem is the mismatched expectation:
Marketing (getting their data from Engineering) proudly trumpets this
performance, but defines it as an AVERAGE over the entire installed base.
Each customer, however, assumes it means a guarantee for himself alone. You
can't have it both ways.
In fact, my employer has analyzed such data from that part of the installed
base that reports back home, and in fact they claim 99.999% overall. (I
wasn't privy to the definition and selection of outliers, but I'll bet
there are some.) Not a network, just a bunch of boxen, but still.
And remember: half the population[1] has an IQ below 100. :-)
[1] Yes, I know the difference between mean and median, but that's not
funny.
