Will FDDI ring work without OS?

[Martin Robinson]

We have a four-node FDDI ring. One of the system in the ring is going to be decommissioned by removing CPU, memory and disk.

If this empty chassis is powered on, will the FDDI ring be complete or does there need to be an operating system running?

We want to avoid re-wiring to a three-node ring as a new server will be delivered soon to restore it to a four-node ring.

[John Bolene · Accepted solution]

Depends on if you have a dual ring, which is a real good thing.

OS has to be there to load drivers for the card and have the card functional, otherwise it is just a light source coming into a port on a non-functioning card.

The dual ring will route back around the other way to get to both sides of the ring.

[rick jones]

Since you mention having a four-node ring, it implies you are either using a concentrator, or are using DAS (dual attach) cards in at least two of the four nodes. I will assume that if you have DAS NICs you have them in all four nodes.

If you are using a concentrator, it should be smart enough to remove the downed node from the "ring" and all should be well.

If you are using DAS, then if this is the only downed node in the ring, the "natural forces" :) of FDDI should do wrap-around and reform the ring using the secondaries.

If you are using DAS cards, it would be better long term to cable around the system being removed.

Something as simple as a basic coupler to join the two "cables" coming to the decomissioned box would be a decent first start, but would mean the ring is still running wrapped (iirc) but with just three nodes that might actually be OK. Better still would be an optical bypass switch in place of the removed node. Best of all is joining the A's and B's of the systems on either side of the removed node