An administrator wishes to deploy network storage that provides block-level disk access. The solution must use the existing Ethernet infrastructure. Which of the following would BEST achieve this?

NAS provides file-level access using protocols such as NFS or SMB, not block-level access.

CIFS is a file-sharing protocol that operates at the file level, not the block level.

Fibre Channel provides block-level access but requires dedicated FC switches and host bus adapters, not the existing Ethernet infrastructure.

iSCSI (Internet Small Computer Systems Interface) encapsulates SCSI commands within TCP/IP packets, enabling block-level disk access over standard Ethernet without requiring dedicated storage networking hardware. Because it runs over the existing Ethernet infrastructure, it eliminates the need for Fibre Channel switches or host bus adapters. This satisfies both the block-level access requirement and the constraint of leveraging existing Ethernet cabling and switches.

DAS connects storage directly to a single server and is not a network storage solution.