Simplex fiber for connecting 2 switches with SFP

[Mathis]

Hello !

I'm looking to connect 2 meraki switches located on 2 separate sites using an already pulled fiber, so I'm connecting to a fiber panel, I don't have a choice of fiber type.

This fiber is a Multimode SC Simplex, which means it has only one port, as opposed to the usual 2 on a duplex fiber (more common).
It then connects to the meraki switch using a simplex SFP, which has just one port. The one I use looks like this: 

 And it will juste connect like this: 

The ones i use are CISCOSOLIDOPTICS GLC-BX-U20-SO.

I have the same 2 SFP models on the 2 switches, but despite this, I can't establish communication.

Meraki recognizes the SFP, as you can see here:

I wonder if it's a question of SFP compatibility, or if I've simply failed somewhere?

If you have any references for simplex SFPs that work on Meraki, i take !

Thank you!

[Brash]

The official Meraki SFP compatibility matrix is linked below.

I don't believe any of those listed are simplex transceivers.

Small-Form Factor Pluggable (SFP) and Stacking Accessories - Cisco Meraki Documentation

However, a quick google shows a number of 3rd party simplex transceivers that claim to be Meraki compatible, so assumedly (depending on where their claims come from) they may work in some Meraki devices. Of course, all of these will be without guarantee or support.

If you can, I suggest testing the link with other devices that do support the simplex mode SFP. That should give a clear indication whether it's the link/SFP's that are the issue, or whether it's the Meraki switches that don't like it.

[Mathis]

Hi,

Thanks for your message.

I'd already had a chance to look at the documentation, and it's precisely because I see that there's nothing in simplex on this one that I'm wondering.

For all the "meraki" simplex SFPs you can find on google, I know that the commercial side often outweighs the functional, and I wouldn't be surprised if they were sold as compatible without having been tested.

Especially since there's nothing on "meraki with simplex" subject either on the forum or on other sites.

That's why I'm asking, via this post, if anyone has already tried this out.

As for the link test, I did a laser test to make sure of its condition, and it was positive. I also tested with 2 different types of SFPs to make sure they're still working, but the fact that they're recognized by Meraki gives me somes clues. Sadly i don't have any non-meraki cisco switches with SFP ports available to test them more.

Thanks !

[Brash]

Recognising the SFP and being able to functionally use it are unfortunately fairly different tasks for a device.

I'll allow others here to comment on their experience if anyone else has used simplex fiber with Meraki but my guess is it won't work.

[sveima]

Are you sure that the SFP is a Multimode? It sounds like a singelmode?

Cisco GLC-BX-U20 Compatible 1000BASE-BX-U SFP BiDi Transceiver Module (SMF, 1310nm-TX/1490nm-RX, 20km, LC, DOM)

And also if you have the BX-U in one end, you need the BX-D in the other end. 

[K2_Josh · Accepted solution]

You will likely need to use two intermediary non-Meraki switches or media converters (one at each side) to utilize simplex transceivers, at least for a Meraki-supported solution. For monitoring purposes, there might be a transceiver compatible with one of the Catalyst switches that can send monitoring to the Meraki cloud. 

For utilizing/testing the transceivers, I would carefully configure switch ports in different VLANs from production and test both transceivers together at one site using a patch cable.

[Mathis]

Hi,

Thanks for your help on this !

Indeed @sveima my bad its a multimode ! But the issue is still the same.

So i finally switched it for a duplex multimode, but indeed i think @K2_Josh is right, i need to use a 3rd party converter or something like this, because all the simplex SFP i tried failed to work. 

Thanks again !

[sveima]

Never heard of a MultiMode Bidir SFP, so i think that the bidir SFP you testet with would work. If you had a singelmode fiber.