Make Cisco device and non-Cisco SFP “work” together

Maybe you came across a problem where you have a Cisco switch worth a few thousand dollars but you just don’t have a Cisco SFP which is also not cheap or it had malfunctioned and you are looking for an alternative. I have recently encountered that kind of situation (the first one) but there is a way:)

In IOS just type the command:

service unsupported-transceiver

This command will be displayed in the beginning of the switch configuration. After typing it you will get a scary message saying:

Warning: When Cisco determines that a fault or defect can be traced to
the use of third-party transceivers installed by a customer or reseller,
then, at Cisco’s discretion, Cisco may withhold support under warranty or
a Cisco support program. In the course of providing support for a Cisco
networking product Cisco may require that the end user install Cisco
transceivers if Cisco determines that removing third-party parts will
assist Cisco in diagnosing the cause of a support issue.

Do not be afraid because you know your goal – Make It Work! You should also be familiar with the fact that you could get cut off on your current supporting contract because of using this.

Then add this:

no errdisable detect cause gbic-invalid

This command will not allow a port to go into the errdisable mode (non-operational mode).

Odds that this third party SFP will work are on your side. Today I have encountered a situation where I had put three identical SFPs in a port and only the third one worked, so in a nutshell – luck!

Remember that you could put a third party SFP in a switch, link could get green, you could even see a CDP neighbor but routing won’t work – that is also possible. In fact, almost anything is possible with a third party SFP, so be prepared for the most unbelievable scenarios.

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