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1000BaseSX to 100BaseFX

I recently checked out one of our networks to find that our switches with 1000BaseSX uplinks were connected to, and functioning with, our

100baseFX switches. Also, from what I've been told and seen (from the brief time that I've been here) it has been working this way without errors, for some time now.

My question is: how is this working if one side is gigabit and the other is 100 mbit? (please include gory details)

Thanks

Reply to
Tom
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??? Are you *very* sure about that? 100BaseFX & 1000BaseSX shouldn't even be able to see each other, much less talk to each other!

And I do mean 'see' literally: 100BaseFX uses a wavelength of 1300 nm, and 1000BaseSX uses 850 nm. They shouldn't even detect each others' presence.

On that front you'd have more luck with -LX, which also uses 1300 nm, but even then I have never heard of a 1000BaseLX PHY that does 100BaseFX as a fallback...

Switch make & model? Module types? Inquiring minds want to know :-).

Regards,

Marco.

Reply to
M.C. van den Bovenkamp

I have heard rumours about GBICs with 100 base-FX fibre interfaces - maybe that is what is in the switch?

Reply to
stephen

That would make sense. A quick Google throws up the Allied Telesyn AT-A45/SC as a 100BaseFX GBIC, so yes, they do exist. Didn't know that.

Still, I'd like to know what his setup is :-)

Regards,

Marco.

Reply to
M.C. van den Bovenkamp

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