Hurricane Maria: Summary of communication status - and lack of
nanog at ics-il.net
Thu Oct 5 23:11:44 CST 2017
Broadcast towers that you ruled out often have cell companies on them. Buildings often have cell sites on them. DAS really isn't all that common.
There's usually two, three, four providers on a given tower. My ASR search of Arecibo, PR gives me 19 constructed. Six of them are on known multi-tenant tower owners.
All towers over 200' and some towers meeting various other requirements must be listed in ASR. The tower companies usually list many of them in ASR, but not always.
Crown Castle has 299 sites in Puerto Rico and lists 196 "alternative" sites. These are likely options on various retail rooftops, open land, etc.
American Tower lists 175 sites with about 2/3 of them being typical towers and the other third being random other things that may or may not be developed.
SBA lists 97 sites.
PTI lists 19 sites.
There are likely other tower companies down there as well. My AT&T Towers login isn't working and they appear to have their own sites down there.
It probably adds up with some margin of error.
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----- Original Message -----
From: "Jean-Francois Mezei" <jfmezei_nanog at vaxination.ca>
To: nanog at nanog.org
Sent: Thursday, October 5, 2017 4:50:39 PM
Subject: Re: Hurricane Maria: Summary of communication status - and lack of
got curious about the FCC's definition of "cell site" in the Maria
outages reports in Puerto Rico.
In the Oct 4 report: Arecibo is reported as having 68 cell sites served,
65 being out. (95.2% outage)
The FCC has an "ASR" (Antenna Structure Registration) search for cell
sites, and this points to actual masts (which I assume need some permit
above certain height).
For ARECIBO, there are 31 entries,
That leaves 24 "constructed".
These registrations do not mention which carrier(s) uses the mast. And
include some owners such as Caribbean Broadcasting Corporation which
isn't likiely being used for cellular.
For all of Puerto Rico, it reports 930 ASR registrations. (haven't done
the parsing to see how many are "Constructed" vs Cancelled, granted,
dismantled). Lets assume 900 for sake of discussion.
So the ~1600 quoted by another organisation would have to include more
than just registered antenna masts.
Except for water towers, what other structures would be amenable to
having multiple carrier's antennas?
What is also not clear from such statistics is the fact you could have a
town with an high antenna broadcasting 850 to the whole area, and then
lots of DAS antennas at telephone pole height in the town at 1900 or 1700.
Having the 850 up and running at the top of the hill might cover the
whole town, even if it would represent only 1 of say 50 cell sites in
Similarly, covering a windy road in a canyon might be done with lots of
DAS anetnnas on telephone poles along the way. They may all be down, but
would normally serve 0 population, so is this number of "down" antennas
During the 1998 ce storm in Québec, Hydro Québec was overwhelmed and
asked cities to identify priority sites inside their territories.
It's fancy "point to where the break is based on where everyone reports
an outage" software was useless because many breaks continued to happen
after power had been lost.
So it had to start from where there was power and work its way, fixing
breaks along the line towards those priority sites. (and once done, fan
out from there to power the non priority areas).
In many rural areas, this involved planting new poles for long
distances, rebuilding from scratch. (And only once the poles are up can
the telco restring its wiring).
What the media doesn't show after a disaster is what is still standing,
what is still working. It could be that a large portion of telephone
poles are still standing and intact and only require minor individual
fixes. Or it could be that large swaths ave seen the poles toppled and
new ones needed with new power and telco wiring done from scratch.
Statistics may look bad showing 100,000 without power. But if it is a
single break by a branch it is easy to fix compared to having 1000
breaks by 1000 branches. So again, statistics don't give the full story
on the real extent of damage.
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