I'm trying to get the following setup to work:

ethernet switch <---> media converter <---> fiber cable <---> media converter <---> ethernet switch

The switches are identical tp-link managed gigabit switches; the fiber cable is multimode om2 with LC connectors; and I'm using identical 10GTek media converters.

Unfortunately it doesn't work and I'm not sure where to start troubleshooting. Here's what the setup looks like:

enter image description here

Any ideas? Thanks!

  • 1
    I'd start by doing a loop-back test to see if each MediaTek and SFP can connect to itself. Use a fresh fiber patch cord. The one pictured may have been bent and twisted so much that it could be damaged. Mar 30, 2021 at 17:48
  • What's the SFP module type?
    – Zac67
    Mar 30, 2021 at 18:22
  • 1
    Try different cables - the fiber patch may have been overbent and the black TP looks damaged or badly DIY.
    – Zac67
    Mar 30, 2021 at 20:39

1 Answer 1

  • Don't bend fiber like that, it's sensitive.
  • The black patch cable might be damaged, replace.
  • Check the SFP modules - for gigabit over MMF you'll need 1000BASE-SX (850 nm).
  • Verify SFP compatibility with the converters - quite a few vendors force you to use their branded modules.
  • You can check a fiber port with a simplex cable as loopback.
  • One converter shows 1000M, the other 100M - if they're not of the switching kind that won't work.
  • Thank you! There were two problems - one faulty ethernet cable and the fibre cable was broken too. I replaced those and it worked fine. Weird, because they were both new from the manufacturers.
    – Neil D
    Mar 31, 2021 at 19:03

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