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We need to have fiber connection between two sites (distance less than 300 meters from each other). Currently there is multi-mode fiber connected to old switches working nicely. Now we are updating our switches to 10Gb and trying to connect, but it doesn't work (no signal lights).

enter image description here

  • Are you able to use the old fibre as a draw wire for installing new fibre? Does the budget go that far ? – Criggie Apr 28 at 21:19
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OM1 or OM3 makes a lot of difference. Please check https://en.wikipedia.org/wiki/Multi-mode_optical_fiber . You will see that OM1 cable can carry 10G for 33 meters while OM3 can carry it for 300 meters. OM3 application first started in 1998 but standardized in 2002. Most probably, your fiber is OM1 like your patch cords. Best practice would be

1- Check for markings on physical cable for information
2- Call a cabling company with a fiber tester. They will tell you everything about the infrastructure.

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300m of OM1 will NOT work with 10GBASE-SR, as JFL and kaya atabey have already pointed out. From 2003, it's quite likely OM2 which won't work with 10G-SR either at that distance. Additionally, patch cables should always match the plenum cable, OM1 won't help here either.

You need to make sure what kind of cable you've got. If it is less than OM3 you'll need to redeploy(!) - also consider switching over to SMF - or find a 10GBASE-LX4 transceiver pair. -LX4 is designed for legacy MMF and will just do 300m even over FDDI grade - it might be expensive and hard/impossible to get though. HPE doesn't sell -LX4 any more. There's also 10GBASE-LRM but that maxes out at 200m.

Another, cheaper option would be to test single-strand 1000BASE-BX10 transceivers (J9142B/J9143B for HPE switches). While these are designed for SMF, they should work on MMF as well, on OM1 for possibly as far as 500m (very much like -LX). If they work you could then aggregate the two or possibly more MMF strands. -BX SFPs from HPE are very expensive as well but there are many 3rd party vendors around.

Note that any single flow would still be limited to 1 Gbit/s, but multiple concurrent flows would become possible. Also note that -BX operation over MMF is not within any standard - don't expect support and observe your company policies on that.

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  • I agree that it's unlikely that OM3 whould have been installed in 2003. At the time, OM1 was OK for 1Gb/s at 300m with OS1 for longer runs. – grahamj42 Apr 28 at 0:53
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From the J9150D datasheet you linked, the max transmission distance over an OM1 fiber is 33m.

enter image description here

Thus you need other transceivers, or to change the fiber.

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  • The transceiver is fine - OP said they weren't sure if the fibre between sites was OM1 or OM3. It's likely OM1/2 and, if so, it's the fibre that will likely need to change. – J... Apr 27 at 20:18
  • It if was OM2 it would not change much the issue, the max transmission distance over OM2 for those transceiver being 82m. But yes, changing the fiber is probably the way to go. – JFL Apr 27 at 21:17

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