iSCSI is an industry standard protocol which implements block storage over a TCP/IP network. Windows sees an iSCSI Logical Unit Number (LUN) as a locally attached disk. You can manage the disk just like locally attached storage.
Windows Server 2016 includes both iSCSI target (server) and iSCSI initiator (client) features. You set up an iSCSI target on a server and then use an iSCSI initiator on a client system to access the iSCSI target. You can use both Microsoft and 3rd party initiators and targets, although if you mix and match you need to test very carefully that the combination works in your environment.
With iSCSI, a target is a single storage unit (effectively a disk) that the client computer accesses using the iSCSI protocol. An iSCSI target server hosts one or more targets where each iSCSI target is equivalent to a LUN on a Fiber Channel SAN. The iSCSI initiator is a built-in component of Windows Server 2016 (and Windows 10). The iSCSI target feature is one...
