From: (Device) Interfaces

32-bit transfers at 25 MT/sec., 100 MB/sec. High Performance Parallel
Interface is a unidirectional channel, i.e. you have to have an OUT
cable and and IN cable for bidirectional transfers (you could have
just one, if it's a read-only device like a scanner or write-only like
a frame buffer). HiPPI is not a shared bus, but its frames can be
switched through a crossbar switch (Network Systems is the premiere
vendor).

HiPPI is used for supercomputer-to-supercomputer networking (TCP/IP,
no less), for RAID arrays (from Maximum Strategy, IBM and others),
tape drives (Sony ID-1 drive), frame buffers and increasingly
workstations (SGI and IBM support HiPPI, and 3rd-party Sbus cards
exist for Sun).

Due partly to the high overhead of HiPPI connections, many devices
have elected to separate the control path from the data path. A common
control path in that case is ethernet.

Good resources from the HiPPI Networking Forum on the web at
http://www.esscom.com/hnf/.