Re: dual router vs. single "reliable" router

["Stephen Sprunk" <stephen () sprunk org>]

Thus spake "David Barak" <thegameiam () yahoo com>
> There are many assumptions and statements about
> reliability, but the methodology of how the numbers
> were reached is not present.  If one assumes that one
> has a router which fails very rarely, this would
> dramatically affect network design.  However, this is
> an assumption, not a conclusion.  The assumption of
> the paper is that the Alcatel box has ultra-low
> failure rates, while the Juniper and Cisco boxen have
> relatively high failure rates.  Personally, before I
> let something like this influence my buying/design
> decisions, I'd want to see some serious raw data...

Nearly all the Cisco device failures I've seen were either software or human
problems; actual hardware failure is _way_ down the list.  Also, I've
observed significantly worse reliability among devices specifically designed
to be highly reliable compared to devices simply designed to work.

There are several networks out there using Cisco devices to achieve over six
9's availability, and the way they do that is by extensive procedure review
and rigorous software testing.  Writing more reliable software is certainly
doable, but more-reliable humans aren't likely and more-reliable hardware is
unnecessary.  IMHO.

S

Stephen Sprunk         "God does not play dice."  --Albert Einstein
CCIE #3723         "God is an inveterate gambler, and He throws the
K5SSS        dice at every possible opportunity." --Stephen Hawking