Dynamic Mapping; Static Mapping - Cisco DS-C9216I-K9 Configuration Manual

Chapter 24 Configuring IP Storage

Dynamic Mapping

When an iSCSI host connects to the IPS module using the iSCSI protocol, a virtual N port is created for
the host. The nWWNs and pWWNs are dynamically allocated from the switch Fibre Channel WWN
pool. The IPS module registers this N port in the Fibre Channel SAN. The IPS module continues using
that nWWN and pWWN to represent this iSCSI host until it no longer has a connection to any iSCSI
target via that IP storage port.
At that point, the virtual Fibre Channel host is taken offline from the Fibre Channel SAN and the
nWWNs and pWWNs are released back to the switch's Fibre Channel WWN pool. These addresses
becomes available for assignment to other iSCSI hosts requiring access to Fibre Channel SANs.
When a dynamically mapped iSCSI initiator has multiple sessions to multiple Fibre Channel targets,
each session can use the same pWWN and nWWN as long as it uses the same node name in the iSCSI
login message.
Identifying Initiators
An iSCSI initiator is identified in one of two ways:
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By default, the switch uses the iSCSI node name to identify the initiator.

Static Mapping

With dynamic mapping, each time the iSCSI host connects to the IPS module a new Fibre Channel N
port is created and the nWWNs and pWWNs allocated for this N port may be different. Use the static
mapping method to obtain the same nWWN and pWWNs for the iSCSI host each time it connects to the
IPS module.
You can implement static mapping in one of two ways: system assignment or manual assignment.
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Tip
Static mapping can be used on the IPS module to access intelligent Fibre Channel storage arrays that
have access control and LUN mapping/masking configuration based on the initiator's pWWNs and/or
nWWNs.
If an iSCSI host connects to multiple IPS ports, each port independently creates one virtual N port for
the host. If static mapping is used, enough pWWNs should be configured for as many IPS ports to which
a host connects.
OL-7753-01
By iSCSI node name—An initiator with multiple IP addresses (multiple interface cards--NICs or
multiple network interfaces) has one virtual N port, assuming it uses the same iSCSI initiator name
to iSCSI targets from all interfaces.
By IP address—A virtual N port is created for each IP address it uses to login to iSCSI targets.
System assignment—When a static mapping configuration is created, one nWWN and/or one or
more pWWNs are allocated from the switch's Fibre Channel WWN pool and the mapping is kept
permanent.
Manual assignment—You can specify your own unique WWN by providing them during the
configuration process.
We recommend using the system assignment option. If you manually assign a WWN, you must
ensure its uniqueness.
Cisco MDS 9000 Fabric Manager Switch Configuration Guide
Configuring iSCSI
24-33