Copyright@2014 D-Link System, Inc. All Rights Reserved.
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D-Link Document – User Manual
iSCSI Concepts
iSCSI (Internet SCSI) is a protocol which encapsulates SCSI (Small Computer System Interface)
commands and data in TCP/IP packets for linking storage devices with servers over common IP
infrastructures. iSCSI provides high performance SANs over standard IP networks like LAN, WAN or
the Internet.
IP SANs are true SANs (Storage Area Networks) which allow several servers to attach to an infinite
number of storage volumes by using iSCSI over TCP/IP networks. IP SANs can scale the storage
capacity with any type and brand of storage system. In addition, it can be used by any type of
network (Ethernet, Fast Ethernet, Gigabit Ethernet, and 10 Gigabit Ethernet) and combination of
operating systems (Microsoft Windows, Linux, Solaris, Mac, etc.) within the SAN network. IP-SANs
also include mechanisms for security, data replication, multi-path and high availability.
Storage protocol, such as iSCSI, has “two ends” in the connection. These ends are initiator and
target. In iSCSI, we call them iSCSI initiator and iSCSI target. The iSCSI initiator requests or initiates
any iSCSI communication. It requests all SCSI operations like read or write. An initiator is usually
located on the host side (either an iSCSI HBA or iSCSI SW initiator).
The target is the storage device itself or an appliance which controls and serves volumes or virtual
volumes. The target is the device which performs SCSI command or bridge to an attached storage
device.
iSCSI device 1 (target)
Host 1
(initiator)
NIC
IP SAN
Host 2
(initiator)
iSCSI
HBA
iSCSI device 2 (target)
