On Sat, 19 Jul 2003 07:49:01 -0700, Rich Seifert
>> I just saw this yesterday trying to connect two Nortel fiber modules,
>> one 100FX and the other 1000FX, neither of which (as I learned shortly
>> thereafter) support auto-negotiation.
>> I didn't know anyone still made Ethernet products that don't support
>First of all, there IS NO STANDARD for Auto-Negotiation at 100 Mb/s on
>fiber, much less for negotiation of data rate between 100 and 1000 Mb/s
>(as your post implies). Thus, it is not surprising that products do not
>support such negotiation; I would be surprised by a device that *did*.
>Second, there is no such thing as 1000BASE-FX; there is 1000BASE-SX and
>-LX for fiber.
>Auto-Negotiation was specifically designed for use on twisted-pair
>media; A-N was designed to resolve the difficulties of using the same
>RJ-45 connector for a wide variety of technologies. While we later
>defined a sort of "Auto-Negotiation" for 1000 Mb/s fiber, it is much
>more limited in scope (it resolves only duplexity and flow control, and
>cannot do anything about data rate or signaling method).
Thanks for the information. I haven't worked much with Ethernet over
fiber, and it shows. I coincidentally ran across some
fiber/auto-negotiation information shortly after my post, though some
of it was contradictory so I was going to ask for clarification.