[c-nsp] MTBF for Cisco products

[Jay Hennigan]

Ted Mittelstaedt wrote:

>> jay at west.net skrev man, 03 dec 2007:
>>> Ted Mittelstaedt wrote:
>>>> (assuming a standard bell curve applies to device failures, which
>>>> it generally does)
>>> Actually, hardware failures generally follow a "bathtub curve", almost
>>> an inverse bell curve.  There is a certain amount of infant mortality
>>> where substandard parts will fail immediately or shortly after
>>> installation, bad connections and other mechanical and assembly issues
>>> are discovered or fail in transit, etc.  Then relatively few failures
>>> for a long time, and then a gradual ramping up of failures as things
>>> wear out, capacitors dry up, etc.
>> I think you both agree with each other. The "Bell curve" would
>> describe the age of the devices
> 
> (age of device when it fails)

Actually, my point was that it is not a bell curve plotting the age of 
the device when it fails.

The "bathtub curve" commonly used do describe equipment failures with 
time on the Y axis and number of failures on the X axis starts out 
relatively high with infant mortality, then drops to a low value 
rapidly, and then climbs after a length of time as components wear out.

http://en.wikipedia.org/wiki/Bathtub_curve

-- 
Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
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