Interface down

[wayne loh]

Hi Guys,

Anyone experience before connecting both the Cisco 3750x and Cisco 3850 via SFP module? I assume it shld be plug and play without any futher configuration on the interface, in fact the interface is performed no shut already but show down status.

The transceiver in used for both end is GLX-LH-SMD.

Pls advise..

[Reza Sharifi]

Hi,

Can you make sure the fiber connecting the 2 switches is good?

Also, since your SFP is LH, make sure to use single mode fiber.  Can you verify?

HTH

[wayne loh]

Hi Reza,

Thanks for the comment, I doubt it could be the physical fiber issue.

Yes SFP is LH, but i check it can run multimode within the distance of 550m. Here i found from cisco site.

The 1000BASE-LX/LH SFP, compatible with the IEEE 802.3z 1000BASE-LX standard, operates on standard single-mode fiber-optic link spans of up to 10 km and up to 550 m on any multimode fibers. When used over legacy multimode fiber type, the transmitter should be coupled through a mode conditioning patch cable.

Thanks.

[Reza Sharifi]

Hi,

So, you are using Multi-mode fiber with single-mode SFP? For testing and to eliminate the possibility of being a cable issue, try using a the same type of fiber as the transceiver. Also, you may want to swap the stands on one side of the fiber and test again.

HTH

[dperezoquendo]

In addition to what Reza said, if you're still not getting anything on the interface, I would recommend reinserting the SFP module and check the logs on your switches to verify compatibility. If, for whatever reason, these SFPs are not compatible, you can try the following command to enable 3rd party SFPs:

service unsupported-transceiver