Which protocol allows block storage commands to be sent over standard IP networks?

iSCSI, which stands for Internet Small Computer Systems Interface, is specifically designed to allow block storage commands to be transmitted over standard IP networks. This protocol enables the SCSI commands, which are traditionally used for communicating with storage devices, to be encapsulated in TCP/IP packets. As a result, iSCSI facilitates the use of standard Ethernet infrastructure for storage networking, making it a cost-effective solution for organizations looking to implement SAN (Storage Area Network) capabilities without investing in more expensive proprietary protocols.

This implementation is particularly advantageous because it allows for greater flexibility in terms of network configuration and scalability, leveraging existing network equipment and technologies. iSCSI can also support long-distance data transfer, making it suitable for disaster recovery and remote data access scenarios.

In contrast, Fibre Channel is a high-speed network technology specifically designed for storage networking but does not operate over standard IP networks; it requires specialized infrastructure. Ethernet, while a foundational network technology, does not inherently support the block storage commands in the way that iSCSI does. Token Ring, being an older network standard, is largely obsolete and does not play a significant role in contemporary storage networking practices.