MX to MS Connect with SFP-H10GB Not Working

[pumrum]

I have an MX100 and MS225-24P running the latest stable firmwares (MX 13.28 and MS 9.37). I connected them together with a passive Twinax Cisco SFP-H10GB-CU1M (1 meter copper). I realize it's not officially "supported" - but I've seen other people get it to work, and the weird thing is:

If I connect both ends of the Twinax to two ports on the same device, I get link lights (ie. both ends of the cable plugged into the MX, ports light up; both ends of the cable plugged into the MS, ports light up). If I connect one end to the MX and one end to the MS... no lights.

I've tried connecting before power on, and connecting after power on. I've tried all combinations of the ports on both devices. I've poked around in the dashboard to see if there was a setting to toggle. No joy.

Any ideas?

[PhilipDAth · Accepted solution]

The MX100 does not have an SFP+ port to be able to use 10Gbe.

[pumrum]

I guess that makes sense, assuming the Copper Twinax is not backwards compatible with 1Gbe?

What's got me curious is, when I plug the transceiver into two ports on the MX, why do the link lights come on?

[PhilipDAth]

It is not backward compatible.

The MX100 does not have an SFP+ port.  I don't know how you are even plugging it in.

[MRCUR]

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@PhilipDAth wrote:

The MX100 does not have an SFP+ port.  I don't know how you are even plugging it in.

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I imagine he's plugging it into one of the SFP ports on the MX. SFP+ will physically fit, it just won't work. 

[pumrum]

Yes, that's correct. I see now that SFP+ Twinax is not backwards compatible with SFP ports. The thing that still has me puzzled is that when I plug both ends of the Twinax into the SFP ports on the MX100... the link lights come on. Very weird. In any case, I've got what I need and very much appreciate everyone's help at pointing out the obvious 🙂