Fiber connection from switch to server-No Link

[Rich_Plummer]

Hello Everyone,
I have an Enterasys B5K124-48P2 with a FTLX8571D3BCL-EX SR SFP+ module installed in port 49.
On the other end is a Lenovo 650 with an Intel x520 card and an Intel FTLX8571D3BCV-IT module.
I am using MM 50/125 Tripp Lite patch cable.

The switch recognizes the SFP and no issues jump out that I can see. The card in the server appears to be working fine as well. I did manually set the speed on the server card to 10GB instead of Auto.

Added bonus, I'm pretty new to Extreme/Enterasys and my knowledge of fiber is weak.

I'm not getting a link light between the two of them. Windows reports the cable is unplugged, and the switch is giving me "operator down".

Can anyone give me an idea as to what my next steps would be?
Thanks

[Rich_Upshaw]

Good info. It's nice to see a Layer 1 discussion every once in a while 

[EtherMAN]

Just FYI there is no "auto negotiate" for any 10 gig link... Was not part of the standard. Also in our 6000 or so active edge interfaces going to all kinds of network devices and gear on 100/1000 connections Auto-Auto is the best for anything under 5 years old between vendors. We have nore issues with the 5 to 10 % hard coded interfaces not coming up or coming up half duplex due to technician doing the deployment not knowing to hard code or not hard coding it correctly.

[Erik_Auerswald]

I would extend the prefer auto-auto time frame to the last ten years, at least. 

[Zdeněk_Pala]

I would check "loop" connection B5K - transceiver - patch cable - transceiver - B5K. If that works you will know that those components are good. Good luck