Question about 100base-fx for fibre experts
 

Though this is not directly linked to Linux I think the best network experts are Linux users ;-).

I was wondering if it's possible to replace two 100base-FX fibre connections by two 1000base-SX SFP modules? Or would be it be better to use media converters so the 100base-FX signal can still be used and converted to copper for gigabit switches that don't support FX SFP by themselves? I realise that with SX the distance between nodes is shorter, but in this case the distance is less than 275 metres.

I hope someone can help me out here, since sticking to 100base-FX seems unattractive to me (less and less switches support it by default, which increases price etc).

I'm not very familiar with 100base-fx cards, but if they are 100base (100Mbps) what benefit would you get from media conversion to copper gigabit ethernet(1000Mbps)? Wouldn't the speed be limited to 100Mbps?

I can say that I have had good results with both the cisco 3550-12g switches (they are EOL but can be had cheap and are rock solid, no ipv6 support though) and the 16 port gbic modules for the 6500 chassis. Just be careful if you aren't sourcing the actual gbics from cisco as there are many counterfeits on the market.

You can't mix and match. You need the same standard on both ends of the fiber. If you mean to replace both ends, fine. But I seem to recall Short haul SX is 200 meters on MultiMode 62.5 micron fiber? May need to Google that. If the fiber is working now, don't add another point of failure by adding a media converter. This type of fix usually costs more in the long run because they are not used long enough to make their expense worth while.

Ok, this was bugging me, so I looked it up. The 802.3z 1000Base-SX standard specifies a maximum distance of 220 meters with 62.5/125 µm fiber core, often orange clad, and up to 550 meters with 50/125 µm fiber core, often grey clad. 100Base-FX was often installed with 62.5 µm.

I wasn't sure yet if it was 50 or 62.5. In this case I need to replace the switches that were using FX (one died already, the others will follow soon I'm sure), since only selected models support it now. The documentation from HP seems to state that SX can bridge up to 275m, but if it's a lot less it might be a problem. I'll consider the options and make a choice ;-)

Thx for the info guys!