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 | NOTE: This chapter provides a brief, high level, overview
of the iSCSI Protocol as defined by RFC 3720. For comprehensive
information on the iSCSI Protocol specification, consult RFC 3720
at: http://www.ietf.org/rfc/rfc3720.txt |
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SCSI (Small Computer Systems Interface) is a widely implemented
family of protocols used for communication with I/O devices, particularly
storage devices.
SCSI is a client-server architecture. Clients of a SCSI interface
are called “initiators”. Initiators issue SCSI “commands” to
request services from “targets”. Targets are typically
components, or logical units, on a server.
A “SCSI transport” maps the client-server
SCSI protocol to a specific interconnect. Initiators are one endpoint
of a SCSI transport and targets are the other endpoint. The SCSI
protocol has been mapped over various transports, including Parallel
SCSI and Fibre Channel.
iSCSI is a transport protocol for SCSI, operating at the same
level as Parallel SCSI and Fibre Channel.
iSCSI is a storage transport protocol developed by the Internet
Engineering Task Force (IETF) for transporting SCSI packets over
TCP/IP.
iSCSI provides an interoperable solution that takes advantage
of existing Internet infrastructure and Internet management facilities.
iSCSI does not have the distance limitations associated with
the Fibre Channel storage transport.
The iSCSI protocol enables the transport of Block I/O over
IP Networks. It operates on top of TCP by encapsulating SCSI commands
in a TCP/IP stream.
