fddi

[carl_townshend]

do many people still use fddi, is this just the same as using say my normal fibre links ? or is it old technology that is not really used ?

[jackyoung]

What I share is I seldom find people use FDDI now. But some of them may use it in SNA for fibrechannel. I can't tell the fibre (wavelenght, etc.) is the same as other technologies but the connector is different.

Just my 2 cents.

[jackyoung]

Sorry. Should be SAN....

[glen.grant]

FDDI was used as a backbone connection which involved dual counter rotateing 100 meg rings which built in reduncancy . This was replaced by normal gig fiber backbones . I think you would be hard placed to find anyone still running FDDI anymore as no one is even making parts for it now...

[carl_townshend]

thanks for that, so was only one ring used at a time ? and if one fails the other one is used ?

[mlund]

Hi Carl.

No, it was like a outer and an inner ring. Where the primary (outer) was designed to carry the traffic, and the secondary ring (inner) was used only to carry traffic around the failure domain. When a failure occur the 2 rings where rapped together on each side of the failure. So when a failure exists you use both rings.

However with a little trick you could use both rings to carry traffic at the same time, as two different and separated networks, the drawback of that was when a failure occured, they become shorted to a single network, and instead of having two 100M-rings, you got one.

Regards

Mike