Fiber Distributed Data Interface (Fddi) Adapter; Fddi Single Ring Adapter Service Considerations; Fddi Dual Ring Adapter Service Considerations; Fddi Cabling - IBM R/S6000 7012 300 Series Operator's Manual

Fiber Distributed Data Interface (FDDI) Adapter

The Fiber Distributed Data Interface (FDDI) Adapter attaches the system unit to a FDDI
network. There are two types of FDDI adapters:
The fiber distribution data interface (FDDI) single ring adapter (Type 2–6)
The fiber distribution data interface (FDDI) dual ring upgrade kit adapter (Type 2–7).
The communications link with the FDDI ring is established during workstation initialization;
thus no special operator action is required to start using the ring.
For more information about this FDDI adapter and software, see the Fiber Distributed Data
Interface User's Guide , form number SC23–2426. This manual is shipped with the FDDI
adapter.

FDDI Single Ring Adapter Service Considerations

The single ring adapter provides a communication link to the concentrator. The concentrator
links the workstations together to form a ring. The number of workstations that attach to a
single concentrator is determined by the capacity of the concentrator. The concentrator may
also have other concentrators attached to it to increase the number of workstations in the
ring. Each workstation can communicate directly with any other workstation in the ring.
If any workstation in the ring has a failure that prevents the signal from being passed back
to the concentrator, the concentrator automatically bypasses that workstation to allow
communications to continue on the ring.
When you turn the system unit off or disconnect it from the concentrator, the concentrator
will bypass that connection to keep communications connection good.

FDDI Dual Ring Adapter Service Considerations

The dual ring adapter provides a dual path for communication between the workstations on
the ring. The purpose of the dual path is to provide increased communication availability.
The dual ring may also have more than one concentrator in the ring to provide connections
to other FDDI rings.
If any workstation in the ring has a failure that prevents the signal from being passed on to
the next workstation or concentrator, the FDDI adapter concentrator does a loop back on
the secondary ring to allow communications to continue on the ring.
In the event two workstations or concentrators fail at the same time the ring could become
segmented . That would mean part of the ring would act like a ring within itself, but could not
communicate with the other parts of the ring. Returning either failing workstation or
concentrator to correct working order will restore communications on the complete ring.
When you turn the system unit off, or disconnect one of the FDDI cables, the workstations
or concentrators on each side of the system unit will loop the signal back on the secondary
ring. This will allow continued communications between each workstation on the ring, except
for the one that is turned off.

FDDI Cabling

Refer to Adapters, Devices, and Cable Information for additional cabling information.
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Operator Guide