Filter
Top Products
1-13
Cisco SN 5428-2 Storage Router Software Configuration Guide
OL-4691-01
Chapter 1 Before Configuring SN 5428-2 Storage Router Software
Transparent SCSI Routing Overview
For example, if an iSCSI target were created for WWPN 3100112233445566 in a storage array, and that
WWPN contained LUNs 0 through 2, those LUNs would become available to an IP host as LUNs 0
through 2. An iSCSI driver would see the iSCSI target named eui.3100112233445566 as a controller
with three iSCSI LUNs identified as LUN 0, LUN 1, and LUN 2. Each iSCSI LUN would appear as a
separate storage device to an IP host.
Mapping each IP host to a Fibre Channel address consists of assigning a WWPN to an IP host that is
requesting access to storage; the WWPN is used for presenting the IP host as an FC host to a storage
array. The SN 5428-2 maintains a pool of 62 WWPNs that are assigned to IP hosts requesting access to
storage. When an IP host is granted access, a WWPN is assigned to the IP host and the SN 5428-2
presents the host as an FC host to the storage array. That host continues using that WWPN until it is
finished using the storage. When transparent SCSI routing is deployed in dynamic mode, once the host
is finished using the storage (logged out), the WWPN becomes available for assignment to other IP hosts
requiring access to storage. In static mode, the IP host/WWPN mapping is retained throughout IP host
logins and logouts and throughout storage router reboots.
See Table 1-4 for an example of transparent SCSI routing mapping. In this mapping example, the
WWPN, 200100023D000100, is assigned to the IP host. Using that WWPN, the SN 5428-2 presents the
IP host as an FC host to the storage array. Three devices are made available as local storage devices:
Local Disk (E:), Local Disk (F:), and Local Disk (G:). (Microsoft Windows devices are used as
examples.) The iSCSI target, eui.3100112233445566, has been automatically created and mapped to a
WWPN, 3100112233445566, that was made available by the storage array. To the IP host, the iSCSI
target appears as a controller with LUNs 0, 1, and 2 available. The LUNs are apparent as they are with
the WWPN in the storage array.
Access for transparent SCSI routing is controlled in the IP hosts and the intelligent storage array. In an
IP host, the iSCSI driver is configured with the Gigabit Ethernet IP address of the SCSI routing instance
in the storage router with which the host is to transport SCSI requests and responses. In the intelligent
storage array, access is controlled through its storage management tools. Additionally, access can be
further controlled in the SN 5428-2 through authentication. See the “Authentication Overview” section
on page 1-24 for more information about authentication.
Once the access is configured in the hosts and the intelligent storage array, the SN 5428-2 transparently
routes SCSI requests and responses between hosts and the mapped storage devices.
Figure 1-13 represents the concept of storage mapping and access control for transparent SCSI routing.
In the figure, the SN 5428-2 Storage Router provides three IP hosts with access to disk drives made
available by the intelligent storage array. A single SCSI routing instance in the storage router is
configured with IP address 10.1.2.3 for the Gigabit Ethernet interface. The iSCSI driver in each IP host
is configured to access that SCSI routing instance by its IP address 10.1.2.3 through the Gigabit Ethernet
interface on the storage router. From the perspective of an IP host, each disk drive mapped to it appears
as a locally attached disk drive. From the perspective of the storage array, each host is connected directly
Table 1-4 Transparent SCSI Routing Mapping Example
WWPN assigned to IP
Host
Apparent to IP
Host iSCSI Target Name
LUNs
Apparent
with iSCSI
Target
WWPN of Storage Array
Target
Physical
LUNs
Available
200100023D000100 Local Disk (E:) eui.3100112233445566 LUN 0 3100112233445566 LUN 0
Local Disk (G:) eui.3100112233445566 LUN 1 3100112233445566 LUN 1
Local Disk (H:) eui.3100112233445566 LUN 2 3100112233445566 LUN 2