Dell Emulex Family of Adapters - Manual (Page 1571)

Boot Version 10.2 for NIC, iSCSI, FCoE, and RoCE Protocols User Manual P010097-01B Rev. A
5. Configuring x86/x64 Platforms for the iSCSI Protocol
iSCSI Overview
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5. Configuring x86/x64 Platforms for the iSCSI
Protocol
iSCSI Overview
iSCSI is an IP-based standard for linking data-storage devices over a network and
transferring data by carrying SCSI commands over IP networks. An iSCSI network
consists of one or more iSCSI storage units (targets) connected through a copper or
optical networking cable to 10Gb Ethernet network switches and/or IP routers. One or
more servers are connected to this network, which are responsible for transferring data
to or from the storage units.
When an operating system receives a request, it generates the SCSI command and then
sends an IP packet over an Ethernet connection. At the receiving end, the SCSI
commands are separated from the request, and the SCSI commands and data are sent
to the SCSI controller and then to the SCSI storage device. iSCSI also returns a response
to the request using the same protocol.
Constructing a Basic iSCSI SAN
There are three main components that make up an iSCSI SAN:

iSCSI Initiator(s) – The initiator allows a given machine access to the storage
available in the iSCSI SAN. It requests all SCSI operations like read or write. An
initiator is usually located on the host/server side, either as hardware (iSCSI
adapter) or software (iSCSI software initiator). To transport block (SCSI)
commands over the IP network, an iSCSI driver must be installed on the iSCSI
host. An iSCSI driver is included with the Emulex adapter. For more
information on iSCSI initiators, see chapter 9., “Configuring and Managing the
iSCSI Initiator with the iSCSISelect Utility,” on page 1599.

iSCSI Target(s) – An iSCSI SAN has one or more iSCSI targets, which house and
make available the storage used within the SAN. The iSCSI target is the storage
device itself or an appliance that controls and serves volumes or virtual
volumes. The target is the device that performs the SCSI command or bridges it
to an attached storage device. iSCSI targets can be disks, RAID arrays, or even
FC fabrics. For additional information on iSCSI targets, see chapter 10.,
“Configuring and Managing iSCSI Targets with the iSCSISelect Utility,” on
page 1610.

Networking infrastructure – The networking infrastructure in an iSCSI SAN
uses Ethernet transport. The configuration and complexity of the storage
network depends on its intended function and the required capabilities.