At 04:40 PM 4/13/99 -0500, Sean Donelan wrote: [details about fiber mangling cut (no pun intended :-) ]
In ten years (I ordered my first circuit in 1989), I've never gotten a good, coherent answer why any of my diversely, redundent circuits were both out-of-service at the same time due to the same event. Lots of credits, lots of apologies, but never a straight answer why something that should never happen, modulo the end of the world, happened.
Sometime in 1991 or so, when we were moving the SURAnet backbone from university campuses (campii?) to collocation space in MCI POPs throughout the southeast, I was talking to one of the MCI techs about the physically diverse T1s that MCI was contracted to deliver. He said if the same person engineered the routing for the circuits at the same time (which would only be done if it was specified on each order), then we might get lucky. Even if diversity is engineered in at first, shuffling circuits on cross connects and such would decrease the likelihood over time (an amazingly short amount of time) - and he also indicated that after a while, it was unlikely that anyone would even be able to determine on demand the actual path that any given circuit takes... :-/ I certainly hope that the systems for tracking this have improved, and also that they keep better track of DS3s and SONET better than they do DS1s.... but I'm skeptical. have fun out there, dave (now celebrating my 8th year of retirement from running networks :-)
Sean Donelan, Data Research Associates, Inc, St. Louis, MO Affiliation given for identification not representation