What protocol maps SCSI block-oriented storage over TCP/IP?

The correct answer is iSCSI, which stands for Internet Small Computer Systems Interface. iSCSI is a protocol that allows SCSI commands to be sent over TCP/IP networks. This enables the transport of SCSI block storage commands over standard Ethernet, making it possible to use inexpensive networking infrastructure for storage area network (SAN) implementation.

By using iSCSI, organizations can connect storage devices, such as hard drives and SSDs, with servers over a network without needing specific hardware interfaces, thereby enhancing flexibility and simplifying setup. This protocol is particularly valuable in virtual environments, such as those managed by vSphere, because it supports centralized storage for virtual machines, allowing for functions like high availability and failover.

Fibre Channel, while also a storage protocol, operates over its own dedicated networks and does not use TCP/IP, which differentiates it from iSCSI. NAS (Network Attached Storage) refers to a file-level storage architecture that provides data access to multiple clients over a network, but it does not use the SCSI command set directly over TCP/IP. Similarly, SMB (Server Message Block) is a protocol primarily used for sharing files and printer services and does not map SCSI commands over TCP/IP. Thus, iSCSI uniquely fills