Fiber cut in SF area

Wed Apr 15 03:04:12 UTC 2009

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

-------------------------------------
Date: Tue, 14 Apr 2009 15:57:52 -0700
From: Roy <r.engehausen at gmail.com>
Subject: Re: Fiber cut in SF area
To: JC Dill <jcdill.lists at gmail.com>
Cc: nanog at nanog.org
Message-ID: <49E514F0.7000009 at gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

JC Dill wrote:
> Gino Villarini wrote:
>> Good points, some variables are dependant on the network infrastructure
>> of the wireless provider.  Localy, the main 2 providers have a
>> "copper/fiber independent" networks.
>>
>>
> I'm pretty sure the WISPs in the Santa Cruz and Gilroy/Morgan Hill
> areas were all also taken offline due to the fiber cut.  (Roy, can you
> verify, for south county?)  Anyone in those areas who relied on a WISP
> as a backup to their fiber/copper link found that their "redundant"
> system wasn't really redundant after all.
>
> You may want to check (verify) how your 2 main providers handle their
> backhaul.
>
> jc
>
>
It based on where the WISP fiber feed was located but in general they
were all down.  There were some special edge cases that stayed up fed
from distant mountain tops.

It didn't seem to matter who your upstream ISP was, they were all gone.