
Making aerial fiber deployment faster and more efficient - WalterSobchak
https://engineering.fb.com/connectivity/aerial-fiber-deployment/
======
paulgerhardt
This would be a game changer. I live in a connectivity desert (Bay Area,
California). Outside of downtown SF there are virtually no residential options
for Fiber. My house is 100 yards from a fiber pump - the quote to run the line
was $50,000 (the ISP would waive the first $30,000). When I complained to the
tech, he said they only have 7 residential fiber customers in the bay area. If
Facebook really can bring high speed Internet to California they could bring
it anywhere!

~~~
BadassFractal
I don't entirely grok how the Bay can be the IT capital of the world and also
have such poor fiber penetration. I've experienced commercial fiber first-hand
in downtown SF, but that was never an option for residential use. Only
Comcast, Spectrum and a couple of smaller mom-and-pop ISPs mostly focusing on
WLAN.

~~~
kziemio
Because cable has improved enough that no consumers really needs fiber to
their homes. You can get 300-1000 Mbps cable internet now in most places and
it is far more than anyone really needs. Upload bandwidth is the main
limitation of cable internet but that's not a major factor for most people.

If cable internet was still stuck at 25 Mbps or similar, the pressure for
fiber internet would be a lot stronger.

But cable internet got good.

The backwards and scandalous aspect of modern American internet is that the
ISPs managed to roll out 1 TB data caps without being blocked by lawmakers.

~~~
tonyb
This is spot on - A large majority of residential internet customers would see
no difference between a 50/5 plan and a 300/30 plan. I done a significant
amount of consulting in the ISP would and every time we would do mass speed
increases there would be virtually no increase in aggregate traffic levels. As
long as people could go to a speed test and get their subscribed speed they
were happy. An HD Netflix stream takes the same amount of bandwidth no matter
what your max speed is.

Most consumers aren't willing to pay the monthly cost that ISPs would be need
to charge to make overbuilding fiber economically feasible. DSL providers
overbuild with fiber because they can't compete with cable and the rising cost
of maintenance of a copper plant. Some cable providers will do new builds with
FTTH or overbuild when upgrading the existing plant is cost prohibitive. But
overbuilding a working coax plant almost never makes since. Spending millions
of dollars to offer higher speeds at the same price just doesn't make business
sense.

~~~
mrep
Maybe it's a regional thing, but the comcast cable internet my parents have is
absolute shit. They just upgraded from 300 to 600 and that did basically
nothing (still get about 25 mbps most of the time and it occasionally now goes
to 50 mbps in speed tests) and our video conferencing calls stutter all the
god damn time which literally never happened back in my apartment that had
fiber.

------
MayeulC
Hmm, there isn't much info on the tech and how the cable is physically laid.

Here is a forum topic (in French) detailing how it was attempted in France [0]
ca. 20013 to bring the network up to speed. A technician explains[1] that this
method is no longer used on new deployments, because of an unexpected issue:
hunter's stray bullets often severed the cables. An interesting video [2] is
linked in the top post.

Maybe the real innovation is that there is no need for a technician to
supervise the thing. But I doubt it: it could be cheaper to pay someone to
watch it than to deal with the consequences of a failure. Though I am not sure
the one I linked could cross pylons, and as such could be only for HV, not MV
lines.

As usual for a press release, a lot of marketing speech, light on technical
details, and the infographics is bullshit, comparing top-end, almost-future
fiber optics with previous gen technologies (100Mbps twisted pair vs 25Tbps
fiber)

[0] [https://lafibre.info/techniques-deploiement/fibre-sur-les-
py...](https://lafibre.info/techniques-deploiement/fibre-sur-les-pylones-de-
rte/)

[1] [https://lafibre.info/techniques-deploiement/fibre-sur-les-
py...](https://lafibre.info/techniques-deploiement/fibre-sur-les-pylones-de-
rte/msg152201/#msg152201)

[2]
[https://invidio.us/watch?v=ZZ8aioekrhc&t=42](https://invidio.us/watch?v=ZZ8aioekrhc&t=42)

~~~
coolgeek
> hunter's stray bullets often severed the cables

Wait, what? If stray bullets are randomly severing cables - and doing so
"often" \- they should often be randomly hitting other things, in a frequency
corresponding to the size and distribution of the thing(s) being hit.

Pardonnez moi for not reading the article. Je ne parle pas Francaise. But this
doesn't seem like it could possibly be the reason for why this method is no
longer used on new deployments.

~~~
MayeulC
No worries, you still get points for your effort :) (s/Francaise/français/)

This also surprised me, hence the "hard to anticipate" bit in the linked post.
I guess it stems from multiple factors: high voltage lines being very long,
high above ground, and crossing remote areas that might be hunting grounds.
Plus, some prey might actually rest on the wires or pylons.

I should have written "lead shot" instead of "bullets", as that's a better
translation. Such ammunition is commonly used for shooting birds, that can be
located in front of or behind the lines. Fiber twisted around the cable also
increases its cross-section.

It's actually quite likely that they often hit other things, but not human
ones (stats say ~140 hunt accidents per year on average there, ~15 deadly, ~20
non-hunters). The cross section of high voltage lines present during hunts on
hunting grounds is likely bigger than the human one. Plus, hunters tend not to
fire at people or in their general direction, while they don't care about HV
lines.

~~~
coolgeek
Ah, okay, that makes sense now. We call it bird shot here.

Birds are also known to perch upon wires, which is another factor that I
hadn't considered before. (Actually, I wasn't even thinking about birds at
all... I was only considering mammals.)

------
mmmBacon
A big issue with aerial fiber is that the fiber experiences fairly large
changes based on the environment. In areas where there is a lot of lightning,
lightning strikes will cause outages. These outages are not caused by physical
damage to the cable plant but rather due to very fast changes in the
polarization of signals on the fiber (the huge electric field of lightning
temporarily causes refractive index changes in the fiber). These index changes
manifest as fast polarization rotations >1Mrad/s. This rate of change is often
fast enough to make it difficult for current DSP to track. While it can be
possible to track the rate of polarization change, it often comes with a trade
off in nominal performance.

See: [https://pegconference.com/wp-
content/uploads/2018/08/Polariz...](https://pegconference.com/wp-
content/uploads/2018/08/Polarization_Activity_Monitoring_Danny_Peterson.pdf)

~~~
bowmessage
Interesting, but isn’t lightning over in an instant? How long would the actual
disruption period be?

~~~
mmmBacon
From the link I provided it shows the time scales. When the fiber transmission
rate is 10-25Tb/s, these timescales represent non-trivial service disruptions.

From the page 4 of the link below you can see that Africa has the highest
density of lightning strikes.

[https://www.ofcconference.org/getattachment/d0ec1565-ce81-48...](https://www.ofcconference.org/getattachment/d0ec1565-ce81-4897-82c1-e18cb9546c79/Lightning-
Strikes-and-100G-Transport.aspx)

~~~
tinco
What does the transmission rate have to do with whether the disruption periods
are non-trivial? If I read it correctly, the disruptions are on the order of
milliseconds (why did you make us read through a powerpoint slideshow?).

That means not noticeable for most fiber use cases. The only use case I can
imagine that would suffer from this a bit, is telerobotics (i.e. remote
surgery). Unless the fiber path is so long, and the lightning storms so large
that there is a continuous stream of those disruptions.

~~~
mmmBacon
Actually the events themselves are only part of the outage. There has to be
time for the link to come back up (not instantaneous). If the disruption is
minor this might be a few hundred ms. However this is still long enough on OTN
networks to trigger protection switching (scale is 100us). This causes traffic
to be rerouted (disruptive). Additionally during a storm, it’s not uncommon
for there to multiple lightning strikes in the same region. When I say same
region, think the length of the state of Florida.

BTW, Florida was where this phenomenon was first observed; every summer there
would be multiple outages.

The large amount of traffic on the fiber can be an issue and cause congestion
and other problems (25T is a lot of traffic). Furthermore service and
equipment providers have SLAs and outages can cost each money.

Sorry to hear that you felt forced to read a set of slides on the matter.

~~~
tinco
Thanks, interesting! I will recover ;)

------
walrus01
In this thread, lots of people who've never heard of OPGW fiber...

[https://www.aflglobal.com/Products/Fiber-Optic-
Cable/Aerial/...](https://www.aflglobal.com/Products/Fiber-Optic-
Cable/Aerial/OPGW.aspx)

One of the problems with this new thing is that in the event of a fiber cut,
restoration times will be VERY long.

For everybody who's saying "This will be great for fiber to the home!". Sorry,
no. From an ISP perspective this is possibly useful for intercity fiber and
medium to long haul DWDM applications. You're not going to be breaking in/out
of it to add or drop circuits. It'll go point to point from electrical
substation to electrical substation, at each end there will be something like
a 10' cube shaped telecom equipment shelter with the optical line terminal
equipment in it.

~~~
metaphor
When the video mentioned a custom cable design to meet requirements, the first
thing I looked for in the article was details on this:

> _...the resulting [cable] design uses G.657 200 micron fibers with a
> specially tailored aramid configuration and a high-strength, high-
> temperature, track-resistant polymer jacket to survive the requirements of
> this application within a small form factor._

...and the first thing that popped into my mind was a certain pain-in-the-ass-
to-repair weapon subsystem which uses a certain HP/LF transmission line that
also leverages a "specially tailored aramid configuration" inner jacket. Cool
tech, but yikes if commercial ISPs embrace this without seriously considering
sustainability implications.

~~~
walrus01
200 micron fiber vs 250 for cladding diameter is extensively used in new ultra
high strand count ribbon cables. The "aramid" part is just Kevlar jacketing
which is also common in outside plant fiber. It sounds more exotic than it
really is. Google spider ribbon fiber for some details.

------
Falloodude
This is a cool project! What happens when that power line needs maintenance or
replacement? Are you just severing the cable? Wrapping a backup line? Just
doing a splice with new line and moving on?

Seems like this also produces a lot of waste over time if you wrap a power
line, then have to re-do the work 30 years later (or sooner).

~~~
DavidPeiffer
> Seems like this also produces a lot of waste over time if you wrap a power
> line, then have to re-do the work 30 years later (or sooner).

I have no specific expertise in this area. A quick Google search shows MV
power lines have a life of 20-30 years, and aerial fiber lines designed for
~25 years. Facebook's goal is to get people online.

Ideally you'd be wrapping younger power lines and decommission everything at
the end of its useful life. It may be viable to get people reliable high-speed
internet now, and in 20 years the area is developed enough it can support even
better infrastructure that they fund themselves.

Internet now might allow a merchant can list a product for sale online _and_
post a picture, notably increasing sales. Internet in 20 years might be 1,000x
as fast as it is today, and doing things we can't even imagine at the moment.

Hopefully innovation like this helps minimize the disparity in opportunity
between rural and urban areas, and rich and poor countries.

------
ed25519FUUU
This is a really innovative technology from Facebook that has a lot of
potential. Props and hat tip to everyone involved in making it work.

Using existing powerlines is a double-edged sword. That infrastructure really
does exist everywhere in the world. At the same time, if a powerline is cut or
severed, requiring special machinery (or robotics?) to replace the fiber line
is going to be a real challenge and can keep people offline for a very long
time. Hopefully they're thinking of that scenario.

------
ycombonator
Why can’t they trial this in US ? There are literally thousands of cities
without fiber and locked into crappy cable connections.

~~~
jauer
Power lines are increasingly buried (even MV) in cities, so it's not a good
use case for this tech.

Poor connectivity in the US is a political problem, not a technical one.
Google Fiber tried to solve this by getting cities to make permitting not
terrible with mixed results.

~~~
topspin
> Poor connectivity in the US is a political problem, not a technical one.

Correct. Lawmakers in your state have to take steps to clear the way for
broadband. Otherwise lawsuits fly when rent seekers gouge whomever has right-
of-way when data services try to come through. Also, utilities have to be
forced to get off the dime. If they're required to offer non-discriminatory
access to poles and trenches, for instance, then they either seek to operate
the broadband service themselves or come to terms with someone who can.
Otherwise they behave like it's 1975 forever and squat on their power lines.

------
sradman
Very impressive. The problem seems much more daunting than what is typically
tackled with robotics. Kudos to the team. Does this mean that the electric
utilities will be joining the cable tv and telephone utilities in offering
internet services or do the economics only work in locales with electric
transmission right-of-ways alone?

~~~
jauer
This is all middle-mile deployments, so the utility would be leasing strands
to cable/telco/other entities.

There are quite a few routes built on HV power lines. Problem is you get weird
problems like lightning strikes inducing magnetic field that affects
polarization and other things that cause outages. E.g.
[https://www.ofcconference.org/getattachment/d0ec1565-ce81-48...](https://www.ofcconference.org/getattachment/d0ec1565-ce81-4897-82c1-e18cb9546c79/Lightning-
Strikes-and-100G-Transport.aspx)

------
myself248
Deforming the coil of fiber into a U-shape is exactly what happens inside a
standard box of cat-5, if you've ever opened one up. It's basically a figure-8
coil, folded into a U-shape and stuffed into the box. It pays out from the
middle, just like any other figure-8 wrap.

------
alynn
If you want to compare with the manual process for crossing obstacles, here’s
a little buggy with a gasoline motor, with the lineman hoisting it past an
insulator with the help of a pulley, starting around 6:20:

[https://www.youtube.com/watch?v=rtbtlgAGRaA](https://www.youtube.com/watch?v=rtbtlgAGRaA)

Also related, videos of people walking on the cables after being dropped off
by a helicopter onto the live lines:

[https://www.youtube.com/watch?v=9tzga6qAaBA](https://www.youtube.com/watch?v=9tzga6qAaBA)

A youtube search for 'helicopter lineman' turns up a lot of other material in
this vein.

------
HALtheWise
I'm not clear that I'm reading this correctly, but it seems like the basic
setup here was that Facebook had an idea for an innovative hardware solution,
and made it happen by collaborating closely with a few experts in different
related industries. This is notably different than how Google X does things,
or how Facebook has previously worked with Aquila and such, and I wonder
whether it'll catch on as a model.

------
hnarn
Doesn't aerial deployment of fiber have the exact same benefits and drawbacks
as aerial deployment of electricity, or anything else? In my neck of the woods
(northern Europe) aerial deployment of electricity has been frowned upon for a
long time: while cheaper, it is much more likely to cause outages due to
environmental factors (or sabotage), so while digging down cables is more
expensive, it's a lot more cost efficient in the long run because you don't
have to send out technicians multiple times a year to climb poles, fell trees,
patch lines etc. -- so pretty much all new deployments are dug down, and the
most affected lines are converted to ground lines.

I would be interested to hear about these considerations from someone
knowledgeable in electric and fiber nets, maybe fiber is somehow different?

------
dylan604
[https://www.cnet.com/videos/facebook-built-a-fiber-optic-
spe...](https://www.cnet.com/videos/facebook-built-a-fiber-optic-spewing-
power-line-crawling-robot/)

has a video that shows this robot in action

------
fhk
While you are here and looking at fiber! you can run some software I've
started working on.

Still very early so thought I'd add it here to see if people are interested?

The idea is to get a quick map of where the installations would be and give
you a distance cost which can be adjusted based on other factors (aerial v
underground, existing assets etc).

[https://github.com/fhk/tabby_cat/](https://github.com/fhk/tabby_cat/)

[http://broadband.cat/westdesmoines.html](http://broadband.cat/westdesmoines.html)

------
gorgoiler
The robot is cool. The economics feel a bit off kilter for me though. With
tongue in cheek, I raise the following points:

-/ Heaven forfend transferring wealth to the local laborers, to pay them to install this infrastructure. Why waste all that money by converting it into Ugandan wages when it can be spent on robots instead?

-/ Hopefully the fibre and connectivity is only leased to the Ugandans, for a more efficient return on the capital investment.

 _Hmmm._

~~~
apex3stoker
It's for safety. As explained in the article, it is not an option to shut down
power to manually install the fibre because the power outage would be too
long. The installation must be done with power transmission. This work is too
complex for human to do safely.

------
ckdarby
If it runs every 1 km wouldn't that require the fiber to be fused every 1 km?

Don't know who is going to go up to middle voltage lines to do a fiber cable
splice.

~~~
adrianmonk
The article mentions starting two robots from the same point heading in
opposite directions to make that 2km instead of 1km.

But yeah, you'd have to splice it. I wonder if it would be possible to have
the fibers that need splicing take a short detour down a pole to near ground
level and have someone do the splice there.

------
andrewcamel
Does anyone have context as to why FB finances a project like this? Is there
an economic argument (ie expanding FB’s TAM by bringing more people online)?
Or is there something more nuanced about better connectivity means higher
quality and better converting ads? Or is this just a charitable effort?

------
m0zg
Here's what this look like without a robot:
[https://www.teralink.ru/index.php/ru/navivka-vols-
vl/navivka...](https://www.teralink.ru/index.php/ru/navivka-vols-vl/navivka-
na-lep)

------
frandroid
While they have this robot and spool up there, they should look at deploying
double wires for redundancy... That way you can survive multiple breaks on the
line as long as each break is on a different segment.

~~~
dylan604
I'm assuming that they are allowing service loops to be added to the system
just for the purpose of allowing for cuts in the line to be fixed. Of course,
this was just a puff piece for marketing/PR, so there's lots of details left
out. However, now, instead of just the regular crew of linesmen to
install/repair cables, you also have to have a robotics crew along.

------
mNovak
Anyone more experienced with fiber deployments--what happens when one of these
km-long fibers gets damaged in a storm? Can fiber be easily spliced in the
field, or does it have to be substantially replaced?

~~~
radicaldreamer
Requires specialized equipment and training but definitely doable, even in the
field:
[https://www.youtube.com/watch?v=xba2MThR9Ls](https://www.youtube.com/watch?v=xba2MThR9Ls)

------
tinco
The machine looks awesome, but it's so complex. It looks like it wouldn't
survive two seconds in the Ugandan wilderness. Why not just zip tie the
optical cable to the conductor? I bet it could move a lot faster too if it was
just tacking the cable instead of this big helical movement.

~~~
dylan604
i can't tell how much sarcasm to read into the zip tie comment, but no power
company is going to allow the use of zip ties. the twisting of the fibre cable
around the host tension cable is for safety. just attaching a cable to a
suspension cable will affect how the cable behave in the wind.

~~~
lostlogin
My fibre is installed by zip tying the fibre cable to the old copper phone/dsl
cable. This is a rather different voltage and a short length of 10-15m.

~~~
dylan604
that sounds like a bad installer to me. even in my neighborhood, the most
recent additions to the poles have been the fiber cables, and these are even
twisted around the existing bundle. it's not a tight twist, but still wrapped
around though. a wrap will help prevent unwanted sagging. it's really that
simple. for it not to be done just means somebody didn't do their job.

~~~
lostlogin
It would be logical to do that.

The cable is designed to be strung in the air - it has a core to help it do
this as I understand it (and many others are done without a supporting cable).

