Real-Time Networking over HIPPI

                     R. Bettati and A. Nica

              University of California at Berkeley
                              and
            International Computer Science Institute

                         Berkeley, CA

                          April 1995


                           ABSTRACT

HIPPI provides a very-high-speed communication medium, which is
very well suited for a large number of bandwidth-demanding distributed
applications.  Unfortunately, its circuit-switched nature makes it
very difficult to provide real-time guarantees when connections
contend for network resources.  We present a time-division-multiplex
access scheme designed to give timing guarantees to high-speed
connections. We describe the problem of scheduling the access to a
HIPPI network, and show that, although the problem is very unlikely to
be computationally tractable, very simple heuristics give high network
utilizations for moderately-sized networks.  We present the RMP/RMCP
protocol, our implementation of the scheme described in this paper on
the XUNET-West HIPPI testbed.