I cannot get switch to communicate via Fiber. As soon as sfp is plugged into port, error comes up.

Posted on 2008-06-12
Last Modified: 2008-07-01
When I plug SFP into port with or with out fiber. I get the error "Port is Error Disabled".
Question by:Brent_Austin
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Expert Comment

ID: 21775064

To reenable them just do a shut and no shut. You can configure it to come back automatically on some system, I have to check on that one. But that will only happen if the source of the problem is cleared.

Regarding how they got that way, there can be many reasons. Here are 3:
1. Too many errors received on the port
2. If portfast is enabled and something is connected that generates BPDUs, BPDU guard will do it.
3. If they were put in a port channel and there were problems with that

Make sure you have logging enabled. If you reenable the port and it error-disables again, a log entry may tell you the cause.

Accepted Solution

RTh0037 earned 500 total points
ID: 21836341
This is caused by different fiber modules, faulty cable or port config mismatches

Author Comment

ID: 21885412

It's alive! It's alive!

Well, it took a couple of commands and replacement of the SFP, but it now works. Seems that the Cisco 2Gb SFP's are NFG, The used Finisar 4Gb SFP's are working ok. Finisar is btw one of the 3 vendors that actually make SFP's for Cisco.

In addition, some commands had to be added to the switch:

coreGIG01(config)#service unsupported-transceiver
coreGIG01(config)#no errdisable detect cause all
coreGIG01(config)#no errdisable recover cause all

Thanks for your help and input.

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Expert Comment

ID: 21887006
So my response was correct in saying that the problem was caused by bad SFP modules, cabling etc.  The only problem with doing no errdisable is that if there are problems in the future it will not cause the interface to drop but instead cause latency and packet loss

Expert Comment

ID: 21892634
My solution should be awarded the points.  I clearly pointed him in the correct direction and advised what was causing the trouble.  

Author Comment

ID: 21898280
RTh0037 should have the points. He did point me in the right direction.

Thanks All


Author Comment

ID: 21898289
After awarding the points this is closed.



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