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Posted by alienchow 19 hours ago

My Home Fibre Network Disintegrated(alienchow.dev)
228 points | 201 commentspage 3
defrost 18 hours ago|
> A main component of why I was in sheer horror was the fact that I had stupidly buried all of these cables under my cement flooring in PVC trunking from my shelter to all of the rooms in the flat.

This I don't quite get .. as I understand it "PVC trunking" is a type of cable channeling / ducting.

I do a lot of cable and pipe layout around houses, farms, workshops, worksites, etc. and it's routine to use pipes / ducting / channels to allow other cables to be threaded through after or to replace bad cables.

As much as cable deterioration sucks it should be a relief to have ducting to pull good through after the bad.

alienchow 18 hours ago||
The electricians mentioned that in order to curve the cables along underneath the floor tiling they couldn't use metal trunking which would cause sharp angles, so they used PVC pipes to do curvy trunking for the fibre cables. I could theoretically pull a new cable through by ripping out the wall outlet if this cable actually fails. You can see it in my earlier homelab post. But due to the length of the trunking and the number of bends, I'm not too sure if I can safely drag a new fibre cable through.

But yeah, maybe it's not that bad after all. I hope it won't get to that point.

defrost 18 hours ago|||
I feel for you & yeah, fingers crossed :-)

One of my love / hates is Australian parrots and cockatoos - fantastic birds, noisy as hell - and they can rip out and shred unprotected wiring from rural camera and sensor systems like winged can openers.

fc417fc802 15 hours ago|||
> due to the length of the trunking and the number of bends, I'm not too sure if I can safely drag a new fibre cable through.

I saw someone commented elsewhere about a plastic bag and a vacuum. Another option to keep in mind is a lubricant intended specifically for the task of pulling cable through a conduit.

ErroneousBosh 13 hours ago||
In the olden days, when things like TVs and VCRs had cabinets made from polystyrene and PVC-jacketed power cables, you'd often find that if something had been put away with the mains lead coiled up on top, it then left a "scar" on the case. This is because the plasticiser in the PVC jacket attacked the polystyrene, leaving the mains lead fragile and brittle and a nasty gooey mess on the case that you couldn't fix.

That's why the leads are wrapped in a polythene bag.

When people started using polystyrene sheet insulation in houses (thankfully they no longer do this!) the cables running inside the walls were affected in the same way, with the PVC insulation rotting off as the plasticiser leached out and attacked the polystyrene. Of course there you had the added joy of having a potential electrical fire with a source of just-about-inextinguishable fuel, the polystyrene foam made of fuel and air.

I wonder if something similar has happened here, something's gotten onto the fibre jackets and pulled the plasticiser out?

Animats 16 hours ago||
Would that be this item? [1] The product description and SKU match.

It's not clear who "FS" is. A reseller? A manufacturer? They seem to be in Singapore. There's no excuse for the external plastic sheath disintegrating. They must have formulated the plastic wrong. The terms specify a 30 day warranty.

Here's a catalog of real mil-spec fiber optic cables.[2] This is overkill for home applications; you put these in a fighter jet.

In between are Telecom Industry Association compliant fiber optic cables. That's what telcos use. There are US manufacturers with real plants and addresses.

[1] https://www.fs.com/products/70220.html

[2] https://www.glenair.com/catalogs/fiber-optics.pdf

wsh 8 minutes ago||
FS.COM Limited (深圳市飞速创新技术股份有限公司, https://cn.fs.com/) was founded in Shenzhen in 2009. They’ve applied to be listed on the Hong Kong Stock Exchange; here’s the draft prospectus from a month ago:

https://www1.hkexnews.hk/app/sehk/2025/107950/documents/sehk...

JoachimSchipper 16 hours ago|||
FS is almost certainly fs.com, who do sell lots of fiber stuff.

I agree that less-than-milspec equipment should survive being installed in a home, but... this fiber didn't. https://news.ycombinator.com/item?id=46572962 seems to be relevant.

unsnap_biceps 16 hours ago||
FS is a US company. They are a fairly reasonable option for third party networking equipment. We run a ton of their SPF+ transceivers in our racks, as they're significantly cheaper than OEM parts and indistinguishable in operation and we've had excellent support the handful of times we needed it over the years.
xorcist 12 hours ago||
This looks like regular hydrolysis, same thing that happens to shoe soles after any number of years.

I don't think it's fair to make fun of the cable specifications, seems to me they held up just fine despite the jacket disintegrating. The article doesn't mention the error rate, but I wouldn't be surprised if it was still zero.

bradgessler 18 hours ago||
What’s the advantage of using fiber optics for home networking over 10Gbe Ethernet?
ggm 18 hours ago||
Many people believe running fibre between buildings, even in ducts, is safer than running copper because you get opto-isolation from lightning.

The second thing is that domestic buildings usually do not come with a consistent ground plane. I worked in a 1960s build purpose made for mainframes and we had ~48v floating between racks at either end of the building and had to do a shitload of work to reground the building, in the 90s (-we were decommissioning an IBM 3033 and deploying a secondhand cray1) the point being somehow, God knows how, prior rs232 serial wiring didn't care and the ground plane for the mainframe was fine at the time. Pre Ethernet this stuff maybe just passed code.

I suspect people who build their own home to some spec acquire these theories. Data comms? Not much reason tbh unless you're pushing a lot more data than normal.

amluto 17 hours ago||
> The second thing is that domestic buildings usually do not come with a consistent ground plane.

Ordinary unshielded copper Ethernet doesn’t care: it’s transformer-isolated at both ends. Shielded cable may object to carrying any substantial amount of current through the shield.

Anyway, there are a handful of good reasons to use fiber:

- Length. Copper is specced for 100m. Panduit will sell fancy copper cable that they pinky-swear works for Ethernet at 150m. Single mode fiber will work at silly long distances.

- High bandwidth. Copper will do 10Gbps. High speed specs exist, but there is approximately zero commercial availability of anything beyond 10G using copper at any appreciable distance. Fiber has no such problems.

IMO if you are running fiber anywhere that makes it awkward to replace (i.e. not just within a single room), use single mode. Multimode fiber has gone through ~5 revisions over the last few decades, and the earlier ones have very unimpressive bandwidth capabilities at any reasonable distance. Even the latest version, where truly heroic engineering has gone into reducing modal dispersion, relies on fancy multistrand cables for the faster Ethernet speeds. Single-mode fiber, meanwhile, continues to work very well and supports truly huge bandwidth at rather long distances, and even decades-old fiber supports the latest standards. And the transceivers for single-mode fiber are no longer much more expensive than multimode transceivers.

amluto 2 hours ago||
Late edit: one exception is A/V. Sometimes you want fiber for applications other than networking. There are A/V applications for fiber, for example. If you need this, use what the thing you’re using the fiber for requires, and consider putting it in conduit. If your application calls for MMF, consider using the highest grade you can get at a reasonable price, which is probably OM4.

Also, preterminated fiber is a thing. While it’s not that hard to terminate MMF, it’s still easier and more reliable to buy preterminated fiber. SMF terminations are apparently much more sensitive to being done perfectly, and buying preterminated fiber is wise. (I’ve never personally terminated any fiber, but I have installed and connected fiber, and it’s delightful to just plug it in.)

alienchow 18 hours ago|||
It's one of those "just because" moments. The idea was to future proof my home infra for a 25G NAS connection. Most ethernet connections tap out at 10G. While theoretically speaking Cat 8 cables can do 40G, hardware support for full 40G Cat 8 NICs is rare. Fibre is very very flexible with its potential bandwidth and SFP28 transceivers are relatively affordable (if you don't do what I did by using SMF. Home networks should only use MMF if the property isn't a mansion.)
sschueller 14 hours ago|||
I still prefer SMF over MMF. It also allows me to "move" where the city fiber comes in and patch it to another location without any active hardware. So I can for example move my router into another room.

I ran SMF and have no regrets. https://sschueller.github.io/posts/wiring-a-home-with-fiber/

aftbit 4 hours ago|||
I'd say the opposite - any fibre in a wall should probably be single-mode fibre (SMF), simply for future proofing. Single mode optics aren't much more expensive and single mode fibre hasn't changed nearly as many times as multi-mode. You can run 25G over the same SMF that once ran 1G - not so with MMF.
ericd 17 hours ago|||
10GbE rj45 (normal ethernet jack) spf modules tend to burn power and get extremely hot, like to the point of burning you if you touch it - the manual for my switch said to leave adjacent ports unoccupied if using one of those. The fiber ones run cool to the touch.

Also, not needing to rerun any cabling if we want to bump up speeds in the future, you just change the laser module on either end. These should be good to >100x current speeds. Not the case with copper.

crote 16 hours ago|||
"10GBASE-T runs hot" is only half true.

The real problem here is that 10GBASE-T is ancient. The spec dates back to 2006! And worst of all: it only saw lukewarm adoption by the datacenter industry, so there hasn't really been a reason for manufacturers to refresh their lineups. This means that SFP+ transceiver you buy in 2026 might be using chips manufactured using a 20-year-old node. No wonder it is running hot!

2.5GBASE-T and 5GBASE-T are essentially using the same technology, but you don't hear anyone complaining about it running hot: hardware for this only recently started to become available due to consumer demand, so any hardware for that is being manufactured using more modern technology, which means a lower power use.

It's still going to consume more power than fiber, but a modern 10GBASE-T SFP+ transceiver should not be burning hot.

ericd 7 hours ago|||
Ah, thanks! That helps explain why it seemed like a sort of poorly executed/ill conceived product. Any good brands you know of? I think I just got something random from FS.com or maybe even Amazon.
userbinator 15 hours ago|||
Realtek recently made a new 10GBASE-T NIC that consumes much less power:

https://www.servethehome.com/cheap-10gbe-realtek-rtl8127-nic...

bob1029 14 hours ago|||
Fiber runs cool because it's operating well within the physical capacity of the channel. Copper needs an incredibly high signal to noise ratio to overcome the limitations of its medium. Copper will consume 5-10x more power than fiber for the same # of bits transmitted.
crote 16 hours ago|||
10G is looking to be the end for twisted-pair copper.

25GBASE-T and 40GBASE-T were standardized 10 years ago, but there are still basically zero products available with support for it. The datacenter market just wasn't interested and chose to use fiber and DAC instead. Worst of all: it requires Cat8 cables and is limited to 30 meters. This means it can't reuse existing cabling, and doesn't have the reach for many home applications - OPs blog post mentions the longest run in their apartment being 55 meters.

Combine that with the general death of wired networking for home & office use, and it is extremely unlikely the market of hardcore tech enthusiasts is big enough to warrant massive investments into developing some kind of 25G-over-Cat6-for-100m standard.

10G is pretty much the standard for high-end gear these days. This means any kind of future-proof setup needs to be prepared for a future upgrade to a fiber-based technology.

fulafel 16 hours ago|||
Ethernet can be run over copper or fiber cabling, it's not an alternative to fiber networking. Assuming you meant what's the advantage of fiber over copper: you can use faster speeds, longer distances less power on fiber plus it's not electrically coupled.

(speeds: 100 gig today, but faster speeds are coming.)

clhodapp 18 hours ago|||
They get less hot (especially the network adapters on the ends of them), can go a lot further, can be a lot denser (including being able to carry things other than Ethernet in the same bundle), and are a lot more future-proof (unless the cable jacket literally crumbles at the slightest movement in a few years).
__turbobrew__ 7 hours ago|||
For me, I wanted my networking to be future proof over the next 25 years if Im going to be putting all that work in to wire up the house. My ISP already offers 5Gb/s upstream and will most likely offer 10Gb/s in the coming years.
rconti 5 hours ago||
I'm kind of going the opposite way. I've got 10gig internet, and I planned on running fiber for future-proofing in our remodel, but the past 20 years has taught me that fiber's day is coming "real soon like now" for a long time... and then copper keeps up because everyone uses it.
toast0 17 hours ago|||
If they're using spf+, it's almost certainly ethernet on the fiber. Do you mean, why not use copper twisted pair?

Ethernet runs on many mediums, as well as over the ether.

tbrownaw 18 hours ago|||
I kinda want some just 'cause it's cool, with the only problem being that I haven't been able to find an excuse to justify (to myself) needing it.
mdswanson 18 hours ago|||
Also much lower power and heat.
20after4 17 hours ago||
This is the most compelling reason (unless you really need the range of fiber) - 10GbE can be really power hungry. Each 10G switch port that is in use adds something like 1-5 watts to the power budget. 1 watt is reasonable but most switch hardware isn't nearly that efficient. That could mean 10 watts for every single link if you're using 5 watts at each end. Multiply that by several links and it starts to add up really quickly.
FireBeyond 18 hours ago|||
For me, it was for a nearly 100ft run that try as I may to get a good termination, I'd often find my Mac Studio and Ubiquiti EdgeSwitch struggle to negotiate at more than 5gbps. So I got a smaller switch upstairs, ran 10GbE to it, approximately 10ft, and then ran OM-3 fiber for the 100ft up into my attic, across my house and down into the garage. Rock solid at 10 Gbps.
reactordev 18 hours ago||
Server-grade fiber optics can get to terrabit/sec speeds. In other words, ludicrous speed.

(He’s gone, plaid!)

melchebo 7 hours ago||
First question, bomb shelter??

Next what popped in my head, “Military grade means, made by the lowest bidder.”

Havoc 11 hours ago||
That's weird. Only place I've seen a rapid degradation of cables were those getting direct sunlight.

The conclusion paragraph seems doubtful to me though - unlikely that speeds will slow down from a cables external plastic flaking

LoganDark 11 hours ago|
I imagine there could be some slowdown if the exact wavelength of the transmission also happens to come in from outside where the jacket is missing.
Sesse__ 15 hours ago||
FS.com is great for all kinds of fiber stuff… but curiously, nothing long-distance. I never really understood it; you can get a 40-channel DWDM setup (including tunable 100gig SFPs) just like nothing, but a drum of quite normal G24 loose tube cabling meant for outdoor use? Nope. You'll have to go elsewhere for that. And I guess that's also what happened here; the poster picked the best thing they had for the purpose, and it's just not that good.

I've also had problems with their pigtails also being weird, by the way (layers separating so that automated cutters can't stretch the pigtail properly). It's weird when everything else is so good—it's as if they only care about what's going on internal to a data center and you never need to do a splice. :-)

sschueller 14 hours ago|
I can confirm the pigtails issue. They are a huge pain to strip for whatever reason. Even cheap ones from AliExpress work better.
mikelabatt 11 hours ago||
Was there a technical reason for not using corrugated ducts in the concrete, maybe because it's a shelter?
adastra22 16 hours ago||
FYI "military grade" is code for "cheapest bidder."
subscribed 10 hours ago|
So what should I buy, "telco"?
oakwhiz 14 hours ago|
If it's any consolation, you can have fiber without jackets as long as they are cable-managed very carefully.
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