-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu]On Behalf Of Art Houle Sent: Wednesday, April 24, 2002 1:52 PM To: Pete Kruckenberg Cc: nanog@merit.edu Subject: Re: The Myth of Five 9's Reliability (fwd)
How to calculate uptime and get 5 9s
-do not include any outage less than 20 minutes. -only include down lines that are actually reported by customers. -when possible fix the line and report 'no trouble found'.
These can all accomplished with one simple and elegant system policy rule. It also has the advantage of "tuneability". If you hold off determining if there is an interruption of service for X minutes, then NO interruptions of service shorter than X minutes exist, since the service is functional when tested. Also, a call center that first "routes" tickets to the "appropriate area" can deliver 99.99 with little effort. ( in fact, the LESS effort/clue, the BETTER the rating ! ) BTW - One of my best friends growing up ( and we took EE together ) grandfather was the V.P. in charge of AT&T's LongLines division while a lot of the "wire was pulled". From what he said of his grandfather's remarks, they didn't think about five 9's. The question was how much spare/redundant capacity did you have, both for dependability and to support the countries growth. Not exactly "this quarter's profit" thinking -sigh-. Bruce Williams "Two is not equal to three, even for large values of two"