WWN, or World Wide Name, is a unique identifier assigned to each Fibre Channel (FC) port or iSCSI adapter. It is used to identify the port or adapter in a storage area network (SAN) or iSCSI network.
There are two types of WWNs: node WWNs and port WWNs. Node WWNs identify the storage system or server, while port WWNs identify the individual ports on the storage system or server.