Source : Free On-Line Dictionary of Computing

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 {router}s and {concentrator}s 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.
     
        (1994-12-13)