We have several buildings on campus. In our main building we have a core switch which is a Cisco 3560X (with a C3KX-NM-1G module installed) and a Cisco SR2024, among other switches. In another building I have a LinkSys SRW2008. These two buildings were connected via fiber between the LinkSys SRW2008 and the Cisco SR2024 switch using a Mini-GBIC MGBSX1 connector on each end.

Over the weekend, the SR2024 died (no power). I'd like to move the fiber connection in the main building to one of the C3KX-NM-1G ports in the 3560X. At first I just moved it, but the port immediately went to error. I removed the fiber from the Mini-GBIC and did a shut and no shut. That has removed the error. I then connected the fiber back, but the port still shows no connection.

Is there something I need to do to get the port to recognize the link? I thought it would do so automatically, but in my very limited understanding of the Cisco IOS, I was obviously wrong.

Can someone help me configure this link so I can get that part of our network back up?


1 Answer 1


I don't think the MGBSX1 is compatible with the 3560X with the C3KX-NM-1G module. It seems these are the transceivers compatible with your switch:


See the compatibility chart at Cisco Gigabit Ethernet Transceiver Modules Compatibility Matrix.

  • Thanks Ron! It looks like the GLC-SX-MMD is the one I need. Do you have any other suggestions or warnings or comments that I should be aware of?
    – Jono
    Feb 23, 2016 at 16:43
  • Are you really connecting two building with multi-mode fiber (not unheard of, but normally MM is inside buildings, and SM is between buildings)? The GLC-SX-MMD is a multi-mode part. With MM, you need to know the cable length and the fiber class to really make sure you can extend 1 Gb that far. With 62.5 micron OM1 cabling, you are limited to a cable length of 722 ft (220 m).
    – Ron Maupin
    Feb 23, 2016 at 16:55
  • Well, now I don't know. What's an easy way to determine what I have?
    – Jono
    Feb 23, 2016 at 18:48
  • I just looked up the MGBSX1 (by the way, Google is very helpful with this). It appears that the GLC-SX-MMD is equivalent. MGBSX1: 1000BASE-SX SFP transceiver, for multimode fiber, 850 nm wavelength, support up to 500 m. GLC-SX-MMD: 1000BASE-SX SFP transceiver module for MMF, 850-nm wavelength, dual LC/PC connector. If it works today with the MGBSX1, it should work with the GLC-SX-MMD.
    – Ron Maupin
    Feb 23, 2016 at 18:56

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