North American Network Operators Group
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Re: SONET ring questions

  • From: Manar Hussain
  • Date: Mon Oct 19 11:24:48 1998 
>How many significant digits do you consider acceptable?  Even in an ideal
>APS environment, link failure detection and protection switching does take
>finite time.  You might get 99.999% uptime, but probably not 99.9999999%.

The thing that always got me was that there never seems to be a mention of
the sampling period for the stat.

>Methinks that you've been subjected to Marketing.  ;-)

Well ... I'll give you 99.9999999% on any system you like - with a sampling
period of say every billion years. I think that allows me to stay down for
the first 100 years, long enough to extend beyong the life of any stressed
sysadmin :)

More seriously - SLA's that specify a sampling period then also give an
indication what is considered too long an outage. If you get just under the
.1% downtime allowed per year all in one go you may well be pretty pissed
at being told the 8 hour outage was within the SLA.

Manar