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Jason Girvin

C3KX-NM-10G Stuck in 1G mode

Hello all,

     Forgive me if this discussion is already posted, but I have a stack of 3 3750X switches with  the master and switch 3 having a C3KX-NM-10G module installed.  However, I can only use 1G speeds in the SFP+ ports (ports 2 and 4).  I originally had a 1G in slot 3, then removed that SFP and placed the 10G SFP in slot 4. The switch did not recongnize the 10G SFP (confirmed via the "sh int stat" command), but I did see light emitting within the SFP.  I verified the fiber cable and SFP functionality/comaptibility with another known good switch.  The 1G SFPs work in all ports, but I can't get the 10G SFPs to green up or even be detected by switch.  I did read the following text from the NM's manual:

When the SFP module in Slot 1 is shutdown, loses link, or is removed, the SFP+

module in Slot 2 turns on. The SFP module in Slot 1 does not work as long as an

SFP+ module is in Slot 2, whether it has link up or not.

     It appears to me that the original 1G SFP has the network module stuck in 1G mode for ports 2 and 4.  I have shut/no shut all NM ports, rebooted, reseated the NM, tried other known good NM's, vetted SFPs and fiber, all to no avail. 

Any wisdom anyone could bestow on me?  I'd be very appreciative.


Jason Girvin

I just saw another member had the same issue and I thought I would follow up.  The issue I had was a bent pin on the switch that cause the module to have a short.  It actually damaged the module.  Unfortunately we didn't catch this until the second module was broken.  Check the pins in the back of the module and ensure that there is no damage.