looking for suggestion regarding 40Gbit home networking

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Hetz Ben Hamo

New Member
May 16, 2019
It's quite hard to believe, but I couldn't find any information about creating a 40 Gbit home network.

My issue is simple: I live in a 3 room apartment. Since I need the 40 Gbit connection between the rooms, a DAC solution is out of the question - since the distance between the rooms is approx. 20-25 meters, so I need to go with a fiber solution.

So, my questions are:
  1. Which cheap fiber cable solution is recommended to connect between the rooms (it's only 1 to 1 points - from the server to a computer, currently without any switch)
  2. Which budget NIC's are recommended (I really don't want to go the Infiniband way)?
  3. Going forward, if I want to upgrade to 100 Gbit network, would I need to replace the fiber cable?


New Member
Jun 17, 2020
San Diego
I'm interested to hear answers 1 and 2.

For 3 - as long as you get OM3 or better and stay within distance limits (100m for OM3), you can do 100G without a cable change.

Scott Laird

Active Member
Aug 30, 2014
Sources disagree about the actual distance limit for 100GBASE-SR4 over OM3. It's either 70m or 100m; I wouldn't depend on anything over 70m. In either case, 25m wouldn't be a big deal.

For NICs, it probably depends on your OS, but generally the Mellanox Connect-X3 cards are the cheapest for 40G use. They work great with Linux and probably Windows, but IIRC have issues with some of the *BSDs and Solaris derivatives. Connect-X4 is newer, uses less power, and has a few more features, but costs quite a bit more.

If you're using 40GBASE-SR4 optics (the cheapest for 40G), then you'll need a somewhat weird fiber cable to connect the two ends, because you need 8 strands for SR4. Look at MTP/MPO trunk cables at fs.com. They're more expensive than normal duplex LC fiber cables. The alternative would be to buy either LR4 or BiDi optics; they both multiplex multiple signals onto a single fiber strand, but they cost quite a bit more. It'd almost certainly be cheaper to buy the SR4 optics and slightly pricier fiber.

Sample prices from fs.com today. 40G SR4 is $39. BiDi is $169. LR4 is $279. A 25m OM4 MTP cable is $180, while an LC-LC OM4 cable would be $29. That MTP price seems high; you might be able to find something cheaper elsewhere.