Problems with Cisco SFPs

Hello All,

I'm having one hell of a time with this problem and it's driving me crazy..

Hardware: 4 Cisco 3750x switches in 2 stacks of 2. Each switch has a 10GB (SFP-10GB-SR) which is connected to its oppisite stack mate for a total of 2 10gb links. Theses two links are configured in a port channel (20GB total).


------------- SWITCH1A--1ft/.5m_Patch_Cord--patchpanel--460ft/140m_Verticle_Cable_Run--patchp anel--3ft/.5m_Patch_Cord--SWITCH2A SWITCH1B--1ft/.5m_Patch_Cord--patchpanel--460ft/140m_Verticle_Cable_Run--patchp anel--3ft/.5m_Patch_Cord--SWITCH2B


------------- The 10GB interfaces will not come active across the 140m cable. If I connect Switch1B to 2B Directly via the patch cables, the ports come active and work as expected. If I install a 1GB SFP across the 140m link it also works. The 10GB Interfaces however never come up, are not errordisabled or have any other abnormality.

What I have done to fix:

-------------------------- Reboot all Switches Replace All Patch cables Move SFP to another port Shut/Noshut Actual interfaces and Portchannel Remove interfaces from portchannel, then above again.

All Cables are OM3 Spec, are brand new and have been tested with a OTDR, fluke meter and have very minimal DB loss (1.1db+/-). All cable connections pass with excellent results. But the 10GB SFPs still fail to come active across the 140m cable.

The OM3 spec and these SFP's (Orig. Cisco) are rated from 300m which is double the length of the installed cable.

Can anybody help me with this before I have to have myself committed???

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I would suggest switching the 2 connectors around because I had a similar issue where the cable installer switched the connectors around by accident. but you say 1 GB SFP works. Pretty tough situation here with no errors. Are the cables SMF or MMF? Here are some links if you have checked them out already. Hope all works out for you.

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sympathize. As I read your description, you took one of the target switches to the other telco and connected the SFPs with one of the patch cables and it worked.

-- did you try both patch cables? (probably)

Assuming the above wa successful, the best next step is to use your power meter to read the transmit power from each SFP using the intended patch cable. Make sure it falls within spec.

After that, read the receive power at the target end with the patch cables installed on the 140M run. Compare to specs published by Cisco.

If the connections fall below minimum, i.e., too much loss, try cleaning all the connectors in the patch panel. if you don't have an inspection scope, maybe your cable contractor does.

Power meter test your infrastructure, be sure to use reference-quality jumper cables and the proper mandrels.

good luck. couple of times this happened to me, drove me up the wall.

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