GLC-SX-MM conection not working in Nexus93180YC-EX

[EduardR]

Hi Everyone

I ask you for your knowledge... We are trying to connect a Checkpoint Firewall with 1G Fiber SFP to a Nexus 93180YC-EX with a GLC-SX-MM SFP, the port goes up in the Nexus, but doesn't link in the Firewall. We though it was the firewall, but when we use the same SFP with the same Fiber patchcord in a nexus 9396PX or a nexus 7706 it goes up normally in both sides.

We tryed to use other ports in the 93180YC-EX (maybe it was something related with the ASICs¿?) but it doesn't work in any other port. 

• The N93180YC-EX has  BIOS: version 07.61 and NXOS: version 7.0(3)I6(1)
• The N9396PX has  BIOS: version 07.17 and NXOS: version 6.1(2)I3(2)
• The Nexus 7706 has BIOS: version 3.1.0 and system: version 6.2(14)

In the three devices we got other 1G SFP working well, also we try changing the modes to auto/auto, 1000/full; change the port to trunk, to access, to a L3 interface, but neither works. 

Have anyone experienced something like this aswell?

[nazimkha]

Is it GLC-SX-MM or GLC-SX-MMD, As I do not see the GLC-SX-MM supported for Nexus 93180YC-EX in the SFP supported matrix
https://tmgmatrix.cisco.com/home

[EduardR]

Sir, i think that is the issue then, we checked the working 1G SFP and just found it is from other reference (SFP-GE-S), we are going to test one of them instead of the GLC-SX-MM and we will provide update here. Thanks at advance

[Dennis Leon]

Hi, 

Today 27.02.2020 I´ve found out the same problem and according to the compatibility matrix we need GLC-SX-MMD because the GLC-SX-MM is not compatible with several C93180 models.

I´ve also found this external blog post talking about the difference between them:

http://www.fiber-optic-transceiver-module.com/difference-between-cisco-sfp-module-glc-sx-mm-and-glc-sx-mmd.html 

We´ll try the GLC-SX-MMD and post the outcomes.

[mclarenh]

I had a similar issue with a 93180YC-EX running NX-OS 9.3(3) where it simply refused to talk to a FirePower 2100 over GLC-SX-MMD optics.

Both the Nexus and the FP would talk to other devices fine using the same optics and fibres.

I confirmed light on both optics (hint: don't ever look directly into optics or down fibre ends. Use a mobile phone camera).

Both ends had speed and duplex manually set to 1000/full.

The Nexus end was showing as down (notconnect), and the FP end indicated the interfaces were up.

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The solution: on the Nexus switch ports, 'no negotiate auto'.  Worked like a charm after that!