Example Scenario - HP Cisco MDS 9216 - Fabric Switch Configuration Manual

iSNS
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m

Example Scenario

The iSNS server provides uniform access control across Fibre Channel and iSCSI devices by utilizing
both Fibre Channel zoning information and iSCSI access control information and configuration. An
iSCSI initiator acting as an iSNS client only discovers devices it is allowed to access based on both sets
of access control information.
Figure 50-46
Zone 1
In Figure
two initiators are in different zones: Zone 1 consists of iqn.host1 and target P1, and Zone 2 consists of
iqn.host2 and target P2. iSNS server functionality is enabled on both switches, SW-1 and SW-2. The
registration process proceeds as follows:
1.
2.
3.
4.
5.
6.
7.
8.
Cisco MDS 9000 Family CLI Configuration Guide
50-70
Using iSNS Servers in the Cisco MDS Environment
SW-1 SW-2
P1
FC
Gigabitethernet 2/1
IP
Network - 1
iSCSI
TOE
iqn.host1
50-46, iqn.host1 and iqn.host2 are iSCSI initiators. P1 and P2 are Fibre Channel targets. The
Initiator iqn.host1 registers with SW-1, port Gigabitethernet2/1.
Initiator iqn.host2 registers with SW-2, port Gigabitethernet3/1.
Initiator iqn.host1 issues an iSNS query to SW-1 to determine all accessible targets.
The iSNS server in turn queries the Fibre Channel name server (FCNS) to obtain a list of devices
that are accessible (that is, in the same zone) by the query originator. This query yields only P1.
The iSNS server then queries its own database to convert the Fibre Channel devices to the
corresponding iSCSI targets. This is based on the iSCSI configuration, such as virtual-target and its
access control setting or whether the dynamic Fibre Channel target import feature is enabled or
disabled.
The iSNS server sends a response back to the query initiator. This response contains a list all iSCSI
portals known to the iSNS server. This means iqn.host1 can choose to log in to target P1 through
either SW-1 (at Gigabitethernet 2/1) or SW-2 (at Gigabitethernet 3/1).
If the initiator chooses to log in to SW-1 and later that port becomes inaccessible (for example,
Gigabitethernet 2/1 goes down), the initiator has the choice to move to connect to target P1 through
port Gigabitethernet 3/1 on SW-2 instead.
If the target either goes down or is removed from the zone, the iSNS server sends out an iSNS State
Change Notification (SCN) message to the initiator so that the initiator can remove the session.
Figure 50-46 provides an example of this scenario.
Zone 2
P2
FC
Gigabitethernet 3/1
iSCSI
TOE
iqn.host2
Chapter 50 Configuring iSCSI
OL-16184-01, Cisco MDS SAN-OS Release 3.x