Dual-attached
The form of
FDDI interface where a device is connected to both FDDI token-passing rings, so that uninterrupted operation continues in the event of a failure of either of the rings. All connections to the main
FDDI rings are dual-attached. Typically, a small number of critical infrastructure devices such as
routers and
concentrators are dual-attached, whereas
host computers are normally single-attached or
dual-homed to a router or concentrator.
For example, a ring could be formed between a single router and two concentrators (all dual-attached) then all other components that need to be fault-tolerant (typically file servers) can be
dual-homed to both concentrators.
