HyperSCSI is an outdated computer network protocol for accessing storage by sending and receiving SCSI commands.
[1] HyperSCSI is unlike iSCSI in that it bypassed the internet protocol suite (TCP/IP) and works directly over Ethernet to form its storage area network (SAN).
It skipped the routing, retransmission, segmentation, reassembly, and all the other problems that the TCP/IP suite addresses.
Compared to iSCSI, this was meant to give a performance benefit at the cost of IP's flexibility.
[2] Since HyperSCSI was in direct competition with the older and well established Fibre Channel, and the standardized iSCSI, it was not adopted by commercial vendors.