HIGH PERFORMANCE PARALLEL INTERFACE

HIGH PERFORMANCE PARALLEL INTERFACE

INTRODUCTION:

The revamped ANSI standard interface is finding a home where high bandwidth is the rule--including workstation clusters and inter-networks.
Network managers on the hunt for high throughput don't have time to play games. Still, they may want to spare a moment to consider this brief riddle: "What do supercomputers, workstations, and other high-end devices have in common?"
"Bandwidth--and lots of it," is the obvious answer. But it's not the only one. How about HIPPI? That's right, HIPPI (High-Performance Parallel Interface). True, the gigabit-per-second ANSI standard was originally developed to allow mainframes and their supercomputing kin to communicate with one another, and with directly attached storage devices, at supersonic speeds. But HIPPI isn't just for supercomputers anymore.
HIPPI’s first aim is to allow high-speed data transfer between different kinds of data-processing devices. It was especially optimized for large block transfers - thereby allowing high peak rates for supercomputers writing on a (parallel) filesystem, but also for interconnection of nodes in a missive parallel system with high volume data transfer between memory.
The HIPPI is a simplex channel, capable of transferring data in one direction only. Two HIPPI channels may be used to implement a full-duplex channel. The HIPPI is a point-to-point channel that does not support multi-drop. The point-to-point limitation considerably simplified the electrical and protocol aspects of the HIPPI. Crossbar switches and other networking methods are being considered to achieve the equivalent of multi-drop. An addressing mechanism is included to support these networking concepts.
Remember that HIPPI is simplex - and point-to-point. The simplex problem was solved simple - another cable will do it. But HIPPI has also facilities that arise the need to have a closer look on HIPPI managing a network of high-speed data processing equipment. Parts of the protocol enable HIPPI to drive special devices - so called HIPPI-Switches. By this means, HIPPI gains the ability to initiate a connection between two dedicated of several devices.
At present HIPPI is the only well-developed technology for gigabit-per-second networks, and as an ANSI standard it will continue to be useful for at least the next five or ten years. When the use of fiber-optic networks becomes widespread, HIPPI will probably serve as a local-network backbone that connects to long-distance links for special applications. Los Alamos has had a prominent and crucial role in the development of HIPPI and continues to refine its capabilities.


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