North American Network Operators Group|
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Re: generators, etc....
In message <Pine.BSI.3.93.961012190050.16602Cfirstname.lastname@example.org>, Michael Dillon writes: > > > Any engineer worth his salt will tell you that > > 100% reliability is unattainable - IMHO, these days with the technology > > we work with daily as young as it is, I'm impressed with 90% uptime... > > I'm not. Five nines quality *IS* attainable and the telcos generally > manage this. Maybe individual components or subsytems will have as low as > 90% uptime, but the entire mesh can be engineered for 99.999% uptime > even with unreliable components like that. Five nines is equivalent to > 8.76 hours downtime per year and that includes scheduled events. You must have missed my half joking posting on the voice system outages we've seen (as just one customer of the voice network). In order to give us 99.999%, Nynex owes us 250 years of flawless service for the one 22 hour outage I mentioned. Since there have been other outages to our voice service, I think we're due for a good 1,000 years of flawaless service to bring us up to 99.999%. If we hold BBN to the same standards that the telco industry uses to come up with 99.999%, BBN was up but "a few customers" experienced a localized outage. This would be brushed off the same as the Illinious AT&T fire at the POP that took out much of the Chicago suburbs for about a week. It doesn't count against the 99.999%. (Otherwise AT&T owes Chicago a couple thousand years of flawless service:). Curtis - - - - - - - - - - - - - - - - -