Brocade Fabric OS Administrator's Guide Supporting Fabric OS v6.3.0 (53-1001336-02, November 2009)

258 Fabric OS Administrator’s Guide
53-1001336-02
iSCSI gateway service overview
12
• Manages iSCSI initiator access control using discovery domains and a discovery domain set
• Session management, such as session tracking and performance monitoring
• Session authentication using CHAP
NOTE
The FC4-16IP iSCSI gateway service is not compatible with other iSCSI gateway platforms, including
Brocade iSCSI Gateway or the Brocade Multiprotocol Router.
iSCSI session translation
The iSCSI gateway enables applications on an IP network to use an iSCSI initiator to connect to FC
targets. The iSCSI gateway translates iSCSI protocol to Fibre Channel Protocol (FCP), bridging the IP
network and FC SAN. The following figure shows a basic implementation.
FIGURE 30 iSCSI gateway service basic implementation
The Brocade FC4-16IP blade acts as an iSCSI gateway between FC-attached targets and iSCSI
initiators. On the iSCSI initiator, iSCSI is mapped between the SCSI driver and the TCP/IP stack. At
the iSCSI gateway port, the incoming iSCSI data is converted to FCP (SCSI on FC) by the iSCSI
virtual initiator, and then forwarded to the FC target. This allows low-cost servers to leverage an
existing FC infrastructure.
To represent all iSCSI initiators and sessions, each iSCSI portal has one iSCSI virtual initiator (VI) to
the FC fabric that appears as an N_Port device with a special WWN format. Regardless of the
number of iSCSI initiators or iSCSI sessions sharing the portal, Fabric OS uses one iSCSI VI per
iSCSI portal.
The following figure shows the interaction of different layers from the iSCSI initiator stack to the FC
target stack, including the iSCSI gateway service used during protocol translation.
iS CS I
initiato r
iS CS I v irtual
initiato r (V I)
iS CS I v irtual
target (VT)
SAN
IP
network
IP
por ta l
FC
por tal
FC4-16IP iSCSI gateway
FC
IP
FC
target 1
FC
target 2
LUNs
LUNs