Which of the following is the BEST method to isolate iSCSI network traffic?

WWPN (World Wide Port Name) zoning is a Fibre Channel SAN fabric construct and is entirely inapplicable to iSCSI, which uses IP addresses and iSCSI Qualified Names (IQNs) rather than WWPNs.

WWNN (World Wide Node Name) zoning is likewise a Fibre Channel mechanism with no relevance to iSCSI networks that operate over IP-based Ethernet.

Because iSCSI encapsulates SCSI commands inside TCP/IP packets and traverses standard Ethernet infrastructure, VLAN segmentation is the appropriate method to isolate its traffic. Dedicated VLANs prevent iSCSI frames from competing with general-purpose traffic, reducing latency and collision domains while improving security and bandwidth predictability for storage I/O.

LUN masking restricts which initiators can access specific storage LUNs at the array level, which controls access but does not segment or isolate network traffic.