Brocade Web Tools Administrator's Guide (53-1000606-01, October 2007)

Web Tools Administrator’s Guide 169
53-1000606-01
About the iSCSI service
14
Terminology
iSCSI target gateway services requires you to understand some additional terminology. Following
are terms that will be used in this document to explain how the iSCSI target gateway is
implemented.
For additional information about iSCSI target gateway, see the Fabric OS Administrator’s Guide.
TABLE 11 iSCSI gateway services terminology
Term Definition
iSCSI Internet-SCSI. A transport carrier of the SCSI protocol over IP.
iSCSI target gateway An intermediate device in the network that allows the iSCSI initiators in an IP SAN to
access and utilize storage in a Fibre Channel SAN. the FC4-16IP AP blade in a
Brocade 48000 director functions as an iSCSI target gateway.
iSCSI port A special GbE port used for iSCSI only. A Fibre Channel virtual initiator is created
behind each iSCSI port running as a proxy Fibre Channel initiator.
iSCSI virtual target A unique target device in the IP SAN that contains LUNs from the real Fibre Channel
targets and is identified by an IQN.
iSCSI initiator A device that begins an iSCSI transaction by issuing a command to another device
(the iSCSI target), giving it a task to perform. Typically, an iSCSI host adapter is the
initiator but targets can also become initiators.
iSCSI session An iSCSI session is the basic communication “pipe” from an iSCSI initiator to an
iSCSI target. A session is a group of TCP/IP connections that link an initiator with a
target (loosely equivalent to a SCSI I-T nexus).
LUN mapping Logical Unit Number mapping. The mapping of the virtual iSCSI target and the
physical Fibre Channel target One frontend LUN (VT LUN) maps to a backend LUN
(Fibre Channel LUN). The frontend LUN numbers can be different from the backend
LUN numbers.
Fibre Channel LUN The LUN identifier of the Fibre Channel target.
VT LUN Virtual target LUN. The LUN identifier of the iSCSI virtual target.
Fibre Channel virtual
initiator
(FC-VI) The iSCSI port looks like an F_Port to the rest of the system. There is one
Fibre Channel virtual initiator per iSCSI. The Fibre Channel proxy initiator solution is
used. FC-VI registers to the Name Server with its symbolic port name (PWWN) and
node name (NWWN). The FC-VI in the Name Server entry is created irrespective of
the host connectivity.
discovery domain (DD) Created between and iSCSI host and iSCSI targets using their IQN for the purpose of
iSCSI device access control.
discovery domain set
(DDSet)
Created using DDs. Can be configured to enable or disable the configuration for the
purpose of iSCSI device access control.
CHAP authentication Authenticates the initiators against a list of user names and passwords with CHAP
(Challenge Handshake Authentication Protocol) authentication in either one-way or
mutual.
IQN An iSCSI Qualified Name that indicates an iSCSI node name in a form that is of
human readable notation using the following syntax:
iqn.yyyy-mm.<reverse of DNS>:<optional iSCSI unique string>
GbE port Gigabit Ethernet port. Uses a copper CAT-5e cable for an IP connection to an RJ-45
copper connector. FC4-16IP has 8 ports of this type that support 1 Gbps speed.
PDU Protocol Data Unit. A unit of data with a header and an optional data section.