[AusNOG] Water in Fibre cables

[Rod Veith]

There are many things that can pierce cable sheaths allowing moisture in without necessarily breaking communications.



The odd rat bite, tree roots, ants, backhoe, termites etc as many years of sheathed copper has shown.



What I‘m curious about now is:



· whether moisture directly against a fibre changes the refractive index of the fibre to an extent that communications is affected.

· The construction profile of fibre cables being laid by the NBN from the exchange (redundant term in the NBN world??) to the home.



It has been many many years since I was last inside a manhole looking into cables. Still remember some on-the-job training and once beating a lead joint into submission shape and turning some brown paper coated wires a slightly darker shade of brown. Gotta respect those blow torches J



Rod



From: ausnog-***@lists.ausnog.net [mailto:ausnog-***@lists.ausnog.net] On Behalf Of Darren Ward (darrward)
Sent: Thursday, 8 March 2012 7:43 PM
To: Jake Anderson
Cc: ***@lists.ausnog.net; Paul Brooks
Subject: Re: [AusNOG] Solar flare



In a PON environment unless you have an unsealed junction/splitter water should be irrelevant?

Sent from my iPhone


On 08/03/2012, at 6:23 PM, "Jake Anderson" <***@vapourforge.com> wrote:

You don't need to be on satellite to suffer from rain fade....
my home Adsl drops ~3mbit (50% of the epic 6 I usually achieve) when it rains.

That's my biggest fear for the NBN, currently a slightly dodgy connection somewhere that gets a bit wet is irritating but not the end of the world, methinks a smidge of water against a fiber is going to be game over.

On 03/08/2012 05:10 PM, Paul Brooks wrote:

And to think I held off posting anything when the alert came through, thinking astronomical discussions would be uninteresting!

If your satellite dishes haven't blown away or floated away in the floods, or been affected by rain-fade within the atmosphere, then the solar wind may well fix your quiet evening.

If you have an interest in being alerted to this sort of thing in the future , www.spaceweather.com has a mailing list you can subscribe to.

This came through at 2:11am this morning, local Sydney time....




-------- Original Message --------


Subject:

Another Major Flare


Date:

Wed, 07 Mar 2012 09:11:44 -0600


From:

SpaceWeather.com <mailto:***@spaceweather.com> <***@spaceweather.com>


To:

SpaceWeather.com <mailto:***@spaceweather.com> <***@spaceweather.com>



Space Weather News for March 7, 2012
http://spaceweather.com

SOLAR ACTIVITY: Big sunspot AR1429 has unleashed another major flare--an X5-class eruption on March 7th at 00:28 UT. As a result of the blast, a radiation storm is underway and a CME will likely hit Earth's magnetic field in a day or so. Geomagnetic storms are already in progress at high latitudes due to earlier eruptions from the active sunspot. Last night, auroras were spotted over several northern-tier US states including Michigan and Wisconsin. Check http://spaceweather.com for updates and images.

SPACE WEATHER ALERTS: Would you like a call when geomagnetic storms are in progress? Space weather alerts are available from http://spaceweathertext.com (text) and http://spaceweatherphone.com (voice).

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Lots of pretty pictures of CMEs and auroras at www.spaceweather.com.

cheers,
Paul.

[Ben Buxton]

· **whether moisture directly against a fibre changes the
refractive index of the fibre to an extent that communications is affected.

On this point - unlikely. As long as the cladding is undamaged, the
refractive properties are unchanged.

The cladding is not the sheath or anything you can see, but basically on
the individual fibres (each fibre is the core+cladding). The chances of
breaking the cladding without breaking the fibre is somewhat remote.

You pretty much have to physically nick the fibre, or get water into an air
gapped joint (eg SC-SC joiner) for performance to be affected. Water
leaking into the sheath should not affect comms if the fibres are
themselves undamaged.

BB

[Michael Christie (micchris)]

· whether moisture directly against a fibre changes the refractive index of the fibre to an extent that communications is affected.

Unless the moisture somehow penetrates the glass, no. Fibres are constructed with a coaxial core and cladding both made of glass with different refractive indexes. The internal reflective boundary (that keeps the light inside the core) is between the grades of glass, not an external glass/air boundary.



· The construction profile of fibre cables being laid by the NBN from the exchange (redundant term in the NBN world??) to the home.

I remember in a previous life specifying optical cables with an armoured housing designed to resist burrowing wombats
.

Not sure NBNCo is going that far.



Mike.



From: ausnog-***@lists.ausnog.net [mailto:ausnog-***@lists.ausnog.net] On Behalf Of Rod Veith
Sent: Friday, 9 March 2012 9:50 AM
To: ***@lists.ausnog.net
Subject: [AusNOG] Water in Fibre cables



There are many things that can pierce cable sheaths allowing moisture in without necessarily breaking communications.



The odd rat bite, tree roots, ants, backhoe, termites etc as many years of sheathed copper has shown.



What I‘m curious about now is:



· whether moisture directly against a fibre changes the refractive index of the fibre to an extent that communications is affected.

· The construction profile of fibre cables being laid by the NBN from the exchange (redundant term in the NBN world??) to the home.



It has been many many years since I was last inside a manhole looking into cables. Still remember some on-the-job training and once beating a lead joint into submission shape and turning some brown paper coated wires a slightly darker shade of brown. Gotta respect those blow torches J



Rod

[Jake Anderson]

·/whether moisture directly against a fibre changes the refractive
index of the fibre to an extent that communications is affected./
Unless the moisture somehow penetrates the glass, no. Fibres are
constructed with a coaxial core and cladding both made of glass with
different refractive indexes. The internal reflective boundary (that
keeps the light inside the core) is between the grades of glass, not
an external glass/air boundary.

The main issue I see would be at cable joins, that's where stuff always
seems to go pear shaped.

·/The construction profile of fibre cables being laid by the NBN from
the exchange (redundant term in the NBN world??) to the home./
I remember in a previous life specifying optical cables with an
armoured housing designed to resist burrowing wombats
.
Not sure NBNCo is going that far.
Mike.

I hope they are in rural areas, they dug out the foundations of my
grandmother in laws house ;->
You know one of the reasons the new power lines they are running are all
twisted together is because Cockatoos don't like to sit on them and chew
the wires (as they do for the current ones)

Does anybody know where one could find what the physical in ground
layout of the NBN is?
IE how does the cable/data get from one of the POP's to a customers
premises?

[Matthew Moyle-Croft]

Does anybody know where one could find what the physical in ground layout of the NBN is?
IE how does the cable/data get from one of the POP's to a customers premises?

Aside from their website? http://nbnco.com.au/rollout/about-the-nbn/what-the-nbn-looks-like.html

MMC

[Jake Anderson]

Post by Matthew Moyle-Croft

Does anybody know where one could find what the physical in ground layout of the NBN is?
IE how does the cable/data get from one of the POP's to a customers premises?

Aside from their website?
http://nbnco.com.au/rollout/about-the-nbn/what-the-nbn-looks-like.html
MMC

That only seems to show how they are cabling a street.
Not if they have some kind of concentrator per 10, 100,1000 houses then
combine those again N times before reaching a POP.

[Damien Gardner Jnr]

*giggle* I just had this vision of an up-scaled version of the old '16
modems on a 64k isdn' (or the more painful 64k satellite!) we used to
suffer through with regional POPs :)

Post by Jake Anderson
That only seems to show how they are cabling a street.
Not if they have some kind of concentrator per 10, 100,1000 houses
then combine those again N times before reaching a POP.

[XiTatiON]

Loading Image...
(sorry not the best picture ever... couldn't find a better one though.)

So basically what happens is a single fiber runs from the OLT to a
passive splitter that you will find in some of the old Telstra poles and
pits around the place. A single fiber is used for TX and RX using
different wavelengths.

The splitter in the pit or in the pole will then split out to 32 fibers
that run to houses that connect to the ONT on the premise which then
provides 4 Ethernet ports and 2 Pots ports which can deliver different
services... e.g Ethernet port 1 could be an IINet internet connection,
Ethernet port 2 could be some kind of IP TV service with Optus, Pots
port 1 could be a Telstra phone. So it will be 32 homes per unlink back
to main OLT and FAN sites.

Hope that makes sense.

Regards,

Jon

Post by Jake Anderson

Post by Matthew Moyle-Croft

Post by Jake Anderson
Does anybody know where one could find what the physical in ground
layout of the NBN is?
IE how does the cable/data get from one of the POP's to a customers premises?

Aside from their website?
http://nbnco.com.au/rollout/about-the-nbn/what-the-nbn-looks-like.html
MMC

That only seems to show how they are cabling a street.
Not if they have some kind of concentrator per 10, 100,1000 houses
then combine those again N times before reaching a POP.
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[Matthew Moyle-Croft]

http://blogs.cisco.com/wp-content/uploads/NBN-fibre-serving-area-550x388.jpg (sorry not the best picture ever... couldn't find a better one though.)
So basically what happens is a single fiber runs from the OLT to a passive splitter that you will find in some of the old Telstra poles and pits around the place. A single fiber is used for TX and RX using different wavelengths.

Splitters are in roadside cabinets. See this photo for an example:

Loading Image...

Top of the cabinet are the splitters - fibre connectors on the back panel are towards the customers.

Moving customers around and connecting them is dead easy, just need a fibre cleaner. You can see how easy it is to reposition customers between splitters if one runs out of bandwidth or you move to a new technology.

MMC

[XiTatiON]

Yup where required new cabinets will be installed...

I believe the plan is to also retro fit into existing spots where
possible, unless this has changed.

Post by Matthew Moyle-Croft

Post by XiTatiON
http://blogs.cisco.com/wp-content/uploads/NBN-fibre-serving-area-550x388.jpg
(sorry not the best picture ever... couldn't find a better one though.)
So basically what happens is a single fiber runs from the OLT to a
passive splitter that you will find in some of the old Telstra poles
and pits around the place. A single fiber is used for TX and RX
using different wavelengths.

http://1mmc.com/pub/nbn-roadside-cab.jpg
Top of the cabinet are the splitters - fibre connectors on the back
panel are towards the customers.
Moving customers around and connecting them is dead easy, just need a
fibre cleaner. You can see how easy it is to reposition customers
between splitters if one runs out of bandwidth or you move to a new
technology.
MMC

[Matthew Moyle-Croft]

Post by XiTatiON
Yup where required new cabinets will be installed...
I believe the plan is to also retro fit into existing spots where possible, unless this has changed.

Not sure how you'd retro fit this into "existing spots" in an even vaguely nice and supportable way.

MMC

Post by XiTatiON

Post by Matthew Moyle-Croft

http://blogs.cisco.com/wp-content/uploads/NBN-fibre-serving-area-550x388.jpg (sorry not the best picture ever... couldn't find a better one though.)
So basically what happens is a single fiber runs from the OLT to a passive splitter that you will find in some of the old Telstra poles and pits around the place. A single fiber is used for TX and RX using different wavelengths.

http://1mmc.com/pub/nbn-roadside-cab.jpg
Top of the cabinet are the splitters - fibre connectors on the back panel are towards the customers.
Moving customers around and connecting them is dead easy, just need a fibre cleaner. You can see how easy it is to reposition customers between splitters if one runs out of bandwidth or you move to a new technology.
MMC

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[Matthew Moyle-Croft]

Post by XiTatiON
Yup where required new cabinets will be installed...
I believe the plan is to also retro fit into existing spots where possible, unless this has changed.

You maybe thinking of the underground plant:

An example of an NBN pit (not reused Telstra one mind you in this photo):

Loading Image...

Top of the pit has the ruggised connector box (preterminated cable into the house) and an example of a fibre joint. No splicing for last bit into your house - just premade leads. Just like FiOS - same Corning solution.

You can see water and mud has gotten into the pit but hasn't affected anything as expected.

MMC

Post by XiTatiON

Post by Matthew Moyle-Croft

http://blogs.cisco.com/wp-content/uploads/NBN-fibre-serving-area-550x388.jpg (sorry not the best picture ever... couldn't find a better one though.)
So basically what happens is a single fiber runs from the OLT to a passive splitter that you will find in some of the old Telstra poles and pits around the place. A single fiber is used for TX and RX using different wavelengths.

http://1mmc.com/pub/nbn-roadside-cab.jpg
Top of the cabinet are the splitters - fibre connectors on the back panel are towards the customers.
Moving customers around and connecting them is dead easy, just need a fibre cleaner. You can see how easy it is to reposition customers between splitters if one runs out of bandwidth or you move to a new technology.
MMC

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[XiTatiON]

Ah yeh that would make more sense :)

The splitters themselves aren't very deep though, could potentially fit
inside lots of things. Weatherproofing and bend radius are things that
need to be considered though.

Post by Matthew Moyle-Croft

Post by XiTatiON
Yup where required new cabinets will be installed...
I believe the plan is to also retro fit into existing spots where
possible, unless this has changed.

http://1mmc.com/pub/nbn-pit.jpg
Top of the pit has the ruggised connector box (preterminated cable
into the house) and an example of a fibre joint. No splicing for
last bit into your house - just premade leads. Just like FiOS - same
Corning solution.
You can see water and mud has gotten into the pit but hasn't affected anything as expected.
MMC

Post by XiTatiON

Post by Matthew Moyle-Croft

Post by XiTatiON
http://blogs.cisco.com/wp-content/uploads/NBN-fibre-serving-area-550x388.jpg
(sorry not the best picture ever... couldn't find a better one though.)
So basically what happens is a single fiber runs from the OLT to a
passive splitter that you will find in some of the old Telstra
poles and pits around the place. A single fiber is used for TX and
RX using different wavelengths.

http://1mmc.com/pub/nbn-roadside-cab.jpg
Top of the cabinet are the splitters - fibre connectors on the back
panel are towards the customers.
Moving customers around and connecting them is dead easy, just need
a fibre cleaner. You can see how easy it is to reposition
customers between splitters if one runs out of bandwidth or you move
to a new technology.
MMC

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[Matthew Moyle-Croft]

They're not very big but when you're reusing Telstra's duct network then it
constrains the design. Imagine one of the fibre cabinets where each of the
current pillars is. That also gives you most flexible and efficient use of
the fibre.



On 09/03/2012, at 13:12, XiTatiON <***@gmail.com> wrote:

Ah yeh that would make more sense :)

The splitters themselves aren't very deep though, could potentially fit
inside lots of things. Weatherproofing and bend radius are things that
need to be considered though.

On 9/03/2012 12:17 PM, Matthew Moyle-Croft wrote:


On 09/03/2012, at 11:42 AM, XiTatiON wrote:

Yup where required new cabinets will be installed...

I believe the plan is to also retro fit into existing spots where possible,
unless this has changed.


You maybe thinking of the underground plant:

An example of an NBN pit (not reused Telstra one mind you in this photo):

http://1mmc.com/pub/nbn-pit.jpg

Top of the pit has the ruggised connector box (preterminated cable into
the house) and an example of a fibre joint. No splicing for last bit into
your house - just premade leads. Just like FiOS - same Corning solution.

You can see water and mud has gotten into the pit but hasn't affected
anything as expected.

MMC



On 9/03/2012 12:09 PM, Matthew Moyle-Croft wrote:


On 09/03/2012, at 11:33 AM, XiTatiON wrote:


http://blogs.cisco.com/wp-content/uploads/NBN-fibre-serving-area-550x388.jpg
(sorry not the best picture ever... couldn't find a better one though.)

So basically what happens is a single fiber runs from the OLT to a passive
splitter that you will find in some of the old Telstra poles and pits
around the place. A single fiber is used for TX and RX using different
wavelengths.


Splitters are in roadside cabinets. See this photo for an example:

http://1mmc.com/pub/nbn-roadside-cab.jpg

Top of the cabinet are the splitters - fibre connectors on the back panel
are towards the customers.

Moving customers around and connecting them is dead easy, just need a
fibre cleaner. You can see how easy it is to reposition customers between
splitters if one runs out of bandwidth or you move to a new technology.

MMC

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[XiTatiON]

Good point.

Post by Matthew Moyle-Croft
They're not very big but when you're reusing Telstra's duct network
then it constrains the design. Imagine one of the fibre cabinets
where each of the current pillars is. That also gives you most
flexible and efficient use of the fibre.

Post by XiTatiON
Ah yeh that would make more sense :)
The splitters themselves aren't very deep though, could potentially
fit inside lots of things. Weatherproofing and bend radius are
things that need to be considered though.

Post by Matthew Moyle-Croft

Post by XiTatiON
Yup where required new cabinets will be installed...
I believe the plan is to also retro fit into existing spots where
possible, unless this has changed.

http://1mmc.com/pub/nbn-pit.jpg
Top of the pit has the ruggised connector box (preterminated cable
into the house) and an example of a fibre joint. No splicing for
last bit into your house - just premade leads. Just like FiOS -
same Corning solution.
You can see water and mud has gotten into the pit but hasn't
affected anything as expected.
MMC

Post by XiTatiON

Post by Matthew Moyle-Croft

Post by XiTatiON
http://blogs.cisco.com/wp-content/uploads/NBN-fibre-serving-area-550x388.jpg
(sorry not the best picture ever... couldn't find a better one though.)
So basically what happens is a single fiber runs from the OLT to
a passive splitter that you will find in some of the old Telstra
poles and pits around the place. A single fiber is used for TX
and RX using different wavelengths.

http://1mmc.com/pub/nbn-roadside-cab.jpg
Top of the cabinet are the splitters - fibre connectors on the
back panel are towards the customers.
Moving customers around and connecting them is dead easy, just
need a fibre cleaner. You can see how easy it is to reposition
customers between splitters if one runs out of bandwidth or you
move to a new technology.
MMC

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[Schulz, Jason]

· The construction profile of fibre cables being laid by the NBN from the exchange (redundant term in the NBN world??) to the home.
I remember in a previous life specifying optical cables with an armoured housing designed to resist burrowing wombats
.
Not sure NBNCo is going that far.

Again in a difference previous life, we went armoured for a specific area in the south of the Sydney CBD after a series of failures due to vermin. There was/is a large concentration of restaurants nearby


Jason.

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