From HiPPI-800 to HiPPI-6400: A changing of the guard and gateway to the future

HiPPI-6400, a high-performance parallel interface running at 6400 Mb/s (800 MB/s), is a networking technology targeted for deployment in a local-area network (LAN) or system-area network (SAN). It is a low-latency, high-bandwidth switch that has the added features of providing flow control and error detection and retransmission in hardware, thus freeing network software from having to implement these functions. Due to the very low overhead of the HiPPI-6400 physical layer and the use of separate control lines, user data rates of HiPPI-6400 are literally 6400 Mb/s or 6.4 Gb/s (eight times the usable bandwidth of Gigabit Ethernet) with an achievable bit-error rate of less than 10²⁵. An initial 32-port HiPPI-6400 prototype, running an OS-bypass network protocol called ST between two 32-node SGI Origin 2000s, produced one-way latencies of 7 μs and sustained data rates of 3.6 Gb/s (unidirectional) and 6.4 Gb/s (bidirectional). The HiPPI-6400 bandwidth in both cases was limited by the memory architecture of the SGI Origin 2000, not by the network. When running an OS-based protocol such as TCP, the unidirectional bandwidth was 2.2 Gb/s