Fiber cut in SF area

Wed Apr 15 03:33:05 UTC 2009

The problem of been LoS is a big problem in metro as far as I know.
You can't just put a pair of FSO gear without going to the building 
owner to talk about rights and cost. Not forgetting lighting protection 
and other stuff.

Murphy, Brian S CTR USAF ACC 83 NOS/Det 4 wrote:
> I haven't seen any mention of the possible use of FSO (Free Space Optics) by the provider to restore some reasonable amount of connectivity during an outage due to a fiber cut.  I would expect that having 2 or 3 pairs of FSO boxes to provide a "reduced failover capacity" in metro areas would be a reasonable measure to ensure service for extended physical (fiber break, cut, backhoe) outages - although not necessarily for power.  Yes, it would take some time to roll them out and set them up, but less time than the crew working the splices, and the folks handling the FSO boxes should be different from the fiber splice truck roll crew.
>
> Note that a power outage would not allow microwave to be an effective remediation method either.
>
> Plus, FSO's use of lasers (vice microwaves) means no issues with spectrum (AFAIK).  Granted, they have limited distance and require LoS, but using two or more pairs can probably handle the 80% situation in the metro (unless there is data to indicate otherwise).
>
> murph
>   