Which protocol is commonly used to access block storage over IP networks in SAN environments?

• A. Fibre Channel (FC)
• B. iSCSI
• C. CIFS
• D. NFS

Answer: (B)

Accessing block storage over IP networks in a SAN is achieved with iSCSI. It carries SCSI commands over TCP/IP, so a remote storage device can appear to the host as a local block device. This lets you use standard Ethernet networks to build SANs, offering cost efficiency, scalability, and features like multipathing.

Fibre Channel is a separate SAN protocol that runs over its own FC networks rather than over IP by default, so it isn’t the typical choice for block storage over IP. CIFS and NFS, on the other hand, are file-level protocols used to access files over a network, not block devices, so they don’t provide raw block storage access to the host.