I have a practical doubt. Can someone explain to me if i can connect 2 networks equipments using XFP and SFP+, MM the two, accross a SM fiber, ´cause i recently made the escenario and did not work.

The 2 connectors, XFP and SFP+ work on 850 nm, on a distance of 300m, every of that a just checked.

The link never came up, but the same link where connected to other slot using 1Gb SFP and instantly came UP.

1 Answer 1


Multimode SFPs (MM) are incompatible with singlemode (SM) fiber.

  • Oh thanks, i see. I was wrong then, ...another question about that, If SFPs MM are incompatible with SM fiber, by some reason, the contrary, SFP SM can work with MM fiber?? Nov 17, 2015 at 16:04
  • 1
    Generally no, although occasionally it will work. But I would never depend on it.
    – Ron Trunk
    Nov 17, 2015 at 16:17
  • @Ron answer is correct in theory. The truth is that sometimes it works. You have here a Cisco case described where you can user MTP to adapt it cisco.com/c/en/us/products/collateral/interfaces-modules/…
    – KorXo
    Nov 17, 2015 at 16:44
  • 1
    Yes, some transceivers that are typically designed for SM can work on MM. However often they will require the use of "mode conditioning" patch cords on each side, and these cables can be more expensive (because they are a require specialized manufacturing and are a low volume seller) than buying the correct optics. See this Cisco document for details.
    – YLearn
    Nov 17, 2015 at 16:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.