A Storage Area Network (SAN) is a dedicated network for block-level data access. Huawei OceanStor systems support a variety of block-access protocols to ensure compatibility with different infrastructure environments. Fibre Channel (FC) is the industry standard for high-performance enterprise SANs, offering dedicated, low-latency, and lossless delivery. iSCSI provides block-level storage over standard TCP/IP Ethernet networks, making it a flexible and cost-effective alternative for many organizations.

InfiniBand (Option B) is a high-bandwidth, low-latency interconnect protocol often used in High-Performance Computing (HPC) and specialized SAN clusters to connect compute nodes to storage pools at extremely high speeds. NFS (Option D) is excluded from this answer because it is a NAS (Network Attached Storage) protocol. NFS (Network File System) provides file-level access rather than block-level access. While modern Huawei systems like the OceanStor Dorado series are 'Unified Storage' (supporting both SAN and NAS on the same hardware), technically, only A, B, and C are considered SAN protocols.