Multiple fiber carriers (was Re: Netrail woes)

Sean Donelan SEAN at SDG.DRA.COM
Tue Aug 26 23:25:26 UTC 1997

>It's one of the questions we ask prior to purchasing service.  Just has 
>MFS install a new ring and put in physically seperate paths to one of our 
>facilities for just that reason.  We made sure the paths were physically 
>seperate when they did the install.  We waited for them to bring fiber up 

Never underestimate Mr. Murphy's ingenuity.  At DRA's main data center
in St. Louis we have three seperate entrance facilities seperated by
a mininum of 50 feet from three seperate carriers.  While I was away
in Munich, an unsupervised MFS tech managed to take down both halves
of one of the self-healing SONET rings.  Gosh, that didn't work, why
don't I do the same thing to the backup ring.  Duh!

I assume if DRA had a fifty-foot crater in front of the building, I'd
likely have other, more pressing problems to worry about.  Unfortunately,
an unsupervised tech can easily, and silently take out multiple diverse
facilities.  Imagine what he could have done with malice and planning.
We try to keep the techs isolated from other carriers equipment, but
techs can be an ingenious bunch when doing dumb things.

Backhoes and other physical disruptions usually have a nice random
distribution modulo the fact that backhoes are often used in right-of-ways.
With the right statistical model, and enough money most folks can come
up with a survivable plan for typical physical disruptions.  On the other
hand, Tech errors are more worrisome, mainly because techs tend to be working
near your most vulnerable points, the nodes that handle failover.
Sean Donelan, Data Research Associates, Inc, St. Louis, MO
  Affiliation given for identification not representation

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