North American Network Operators Group

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Re: generators, etc....

  • From: Steve Norton
  • Date: Mon Oct 14 13:42:17 1996

At 11:56 AM 10/14/96 -0400, Curtis Villamizar wrote:
>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.

Discussion of reliability standards has gotten a little vague.  To throw
some facts into the confusion:

I once managed to beat our Telco reps hard enough for them to provide actual
numbers.  This was after a 4 hour outage on an OC-3 ring that "could self
heal in 50 milliseconds."  Ameritech provided the usual mushroom treatment,
but MFS actually quoted their Operations procedure AP2402, which says:

For a DS3 facility 0-50 miles:
Availability on a 12 month period is 99.997%
Error free seconds > 99.992% over 24 hour period (7 seconds/day)
Bit error rate < 2.5*10E-11
"Performance tests shall be conducted at DS-3 level for 72 hours."

Apparently this is copied from AT&T PUB 62411.  Cisco gives me the mushroom
treatment, but assuming they shoot for something like 99.992% uptime, a
simple DS3 Internet connection could have no better than 99.98% reliability.
Does anyone even come close to this number?  With all of the ATM deployed
recently, I cant imagine any ISP even comes close.

Steve Norton    312-496-4601
VP Operations   312-496-4499  (fax)
InterAccess Co
[email protected]

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