The story of fiber cables in the basement at home

How not to install delicate equipment

Having recently moved in to a new apartment after several years of living in shared student accomodations, I decided that it was finally time to build up my home infrastructure.

The vision is to have a centralized location where all the servers would live in a proper 42HU rack with modern amenities such as redundant three phase power, multiple dark fiber uplinks to the datacenter where my peering fabric resides, and a proper cooling system amongst other things. To achieve this quite ambitious goal though I had to start somewhere smaller, and this blog post describes what I had planned to be the first step of that journey.

Since such an installation of electronic equipment would generate quite some noise and heat, I came up with the idea to install it in the basement. That way I could put all the equipment in a place where it would not bother anybody and still have eveything close enough to go down there and fix things up.

Cabinet of fiber splicing trays fusing the indoor and outdoor fibers Exhibit α: Building entry point consisting of splice trays for each apartment. Right hand side has fiber coming in from the street. If you zoom in you might notice there are actually two bundles and these take different paths in the street to provide route diversity. With normal consumer internet service though usually only one fiber is used giving no redundancy.

I would then run up an MPO-12 multimode cable to my apartment from the basement, which would provide for several ethernet ports as well as a KVM for multiplexing DVI, USB, and audio for my desktop and TV.

In the basement of my apartment building there are storage rooms whih are partitioned using wooden dividers, and luckily for my use case, the unit assigned to me was right next to the technical room where the conduits were run to each apartment for power and FTTH.

Fiber to the Home Singlemode cables going up into conduits Exhibit β: A view of the FTTH Singlemode cables going into the conduits in the technical room. The yellow cables are Singlemode 9/125um cables with 4 strands inside them. The thicker white cables are coaxial running to each apartment and are split from the large black and green cable which is the uplink for the coaxial network.

Unfortunately it was not very clear how the cables ran from there to the apartments, and the labelling on the cables left a lot to be desired. I determined, however, that there was definately a conduit for each apartment going up carrying power, and another carrying the FTTH cable. Since there was not much space in the power conduit and I did not want tomess with that one, I started probing the conduit with a small plastic coated steel braided fish tape which a friend gave me as a housewarming gift.

It was not long enough to reach the other end, so after searching around in the DIY store, I found the one nylon fish tape they had but it too was not long enough. So I did what any engineer would do and duct taped the two together. Unfortunately it kept getting stuck and eventually the duct tape came off somewhere 10m down and the first fish tape was forever lost to the building.

At this point I had already invested several weeks worth of time trying to feed the cable through, and thought that it was time to invest in some more serious equipment. After scouring eBay for good deals I came across a 250' steel tape which surly would be long and strong enough, I thought.

Steel fish tape Exhibit γ: 250’ metal fish tape.

When it arrived I managed to get it further down than before but it was still getting stuck near a sharp bend at the end. Unfortunately I was not able to probe it from the other end of the conduit because I was not sure which one was mine, and I certainly did not want to break a cable which was not my own.

Eventually while trying to get it through, the fish tape snagged the existing fiber and I noticed that there was no more light on my FTTH cable. Turns out that it might not have been such a great idea to try messing with the conduit that was carrying my internet coneectivity.

I wanted to fix the fiber myself and even procured some mechanical splicing tools, but unfortunately the building management had closed off access to the technical room and I had to call the electricity company to fix it. It was certainly one of the more interesting conversations I've had trying to explain to the technician in German why here was the yellow coating of the FTTH cable sticking out of the wall, but I managed to convey the gist of the grand plan and I think he was rather understanding in the end.

Fiber socket in the wall, opened to show the glass strands connecting into the recepticle Exhibit δ: The FTTH socket opened up to show the individual fibers connected to the inside mating connector.

So for now I've just gone back to putting the servers in the closet. Certainly feels a bit sloppy but I guess it works.

Retrospective

What went well

  • I learned a lot about the types of fiber cable and fish tapes.
  • I have a newfound appreciation for people who do cable work.

What went badly

  • I broke the FTTH cable which provides my internet access
  • I spent 3 months trying to pull my cable through the conduit.

Where I got lucky

  • The technician who came to fix the situation was well equipped and I didn't get a bill for the repair.
  • I didn't damage any adjacent equipment in this adventure.

Lessons learned

  • If you have the liberty of designing your own building, install vertical cable shafts and technical rooms in accessible locations to easily install new equipment.
  • If conduits must be installed in concrete, then avoid sharp bends and have multiple cable paths to have more options.
  • Avoid pulling new cables through conduits through existing load bearing conduits.
  • Be prepared for fiber cuts and have backup routes such as a 4G modem which can have an automatic failover.
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Rayhaan Jaufeerally
Senior Intern SRE Graduate