[c-nsp] SFP & GBIC module compatibility

[Bill Wichers]

>>From my understandings, SFP or GBIC are of open standard. And the
>> standard
> modules should work with any router. Is it a marketing ploy that some
vendors (say Cisco reseller) say that we must buy the modules from them
in order have 100% compatibility?
>
> My experience is limited with a few modules that I found to work
cross-platforms without any issues. Would like to know your experiences.

They are *supposed* to be an open standard, but not everyone follows it. I
have generally had good luck with interchangeability between brands (I've
used lots of Finisar optics, for example, which are "just an OEM"). I just
recently had a problem with an HP Procurve switch that worked fine with
Finisar gig LX SFPs, but neither Tyco nor Finisar gig SX SFPs worked. I
eventually ordered an HP Procurve gig SX SFP which worked fine, and when I
checked the vendor ID in the EEPROM of that SFP it came back as Finisar --
even though the Finisar-branded SFP didn't work in the same switch!

My guess is that some manufacturers are reading keys from the EEPROM to
determine if the optic is "authorized" or something like that since I
don't see any other pattern. I suppose that means non-vendor branded SFPs
*might* work, but you should test before saying anything for sure. If they
work they should stay working though, I doubt there would be any
intermittent problems from using another vendor's optics.

    -Bill


*****************************
Waveform Technology
Systems Engineer



*****************************
Waveform Technology
Systems Engineer