Transciever detected but no link

[kbyal]

I have two MS120s that I am trying to connect together via fiber. The transciever is detected but the link never comes up. The fact that the module is detected makes me think it should work (even if it isn't officially supported) 

Has anyone else ran into a similar issue and been able to come up with a solution? I really don't want to have to buy different transcievers if I don't have to.

[alemabrahao]

Is your fiber multimode or singlemode? Have you checked if it is emitting a light signal? Have you tried reversing the fiber pair?

[alemabrahao]

https://www.youtube.com/watch?v=V_xE_3RWOZ0

[kbyal]

Single mode, fiber is transmitting light. Transcievers are BiDi and just confirmed to be working between two MS120-8LP (MS120-24P is the model of the two not working) same firmware.

[alemabrahao]

Well, I've never worked with unsupported transceivers, and as far as I can remember there is no specific configuration to support this. Probably if you open a case with Meraki they will recommend switching transceiver.

What you can try to do is force duplex maybe.

[cmr]

@kbyal if it works MS120-8LP to MS120-8LP, have you tried changing one end to an MS120-24P with no other changes?  i.e. same network, same firmware etc.

[BlakeRichardson]

Are both ends set to auto negotiate? If so try setting speeds manually and try different ports in the switch. 

[Brash]

Given the fact no Meraki switches support SFP-GE-BX transceivers, I don't think you'll get too far with support.

Make sure the fiber pairs are the right way round (swap them if needed).

[PhilipDAth]

I would change to supported transceivers.  As others have said, there is no BIDI support.

[kbyal · Accepted solution]

It turns out two of the fiber stands the on-site tech tried were both bad even though they were passing light. The third strand he tried ended up working. Thanks for everyone's input.

[cmr]

@kbyal did the MS120-8 switches work over the faulty fibres?  I would have thought both switches would fare the same with the same transceivers.

[kbyal]

No, the MS120-8 switches are in production in a different location so when I tested with them they were just connected via a fiber patch that was maybe 3m long. This was mainly to rule out the transcievers as the issue since they were being detected in both models.

The MS120-24 are in two separate buildings connecting via fiber ran underground so without unracking a switch and not having an actual fiber tester we were limited in our troubleshooting.

[cmr]

Thanks @kbyal that makes sense.