StorageTek StorageNet 4000 - Manual (Page 24)

Zone Enforcement
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Zone Enforcement
ZONING is enforced by the Simple Name Server (SNS). ZONING does not change the SNS
protocol. Host device drivers query SNS using existing commands and have no knowledge
that ZONING is in effect. If no zone configuration is in effect, responses to SNS queries are
based on all Fabric connected devices. If a zone configuration is in effect, responses to SNS
queries contain information about only those devices that are in the requestor’s zone.
Multi Switch Fabrics
There are two databases used by ZONING:
• the zone configuration data
• the N_Port login data
Zone Configuration Data
This data is shown as the defined configuration by the cfgShow command, and is stored in
flash by the cfgSave command. This data is a replicated database and all Fabric switches have
a complete copy. Whenever you makes a configuration change, the switch where the change is
made forwards the change to all Fabric switches using vendor unique interswitch protocol.
N_Port Login Data
N_Port Login Data is stored locally on each switch, and is used to translate World Wide
Names into physical port numbers when World Wide Names are used in zone definitions. The
zone checking procedure runs entirely on the local switch when a match can be made by
physical port number alone, but when physical port number is not sufficient, the local switch
has to query the remote switch to get login data. This data is then cached on the local switch
until a State Change Notification renders it stale.
Adding a New Switch
A new switch is a switch that has not previously been connected to a Fabric with ZONING
configured, and has had no zone configuration data entered into it. If a switch has been
connected to a zoned Fabric, or has had zone configuration data previously entered, see the
next paragraph. A switch that has been configured for ZONING may be returned to this new
switch state by using the cfgClear command before connecting it to the Fabric.
When a new switch is connected to a Fabric, all zone configuration data is immediately copied
from the Fabric into the new switch. If a zone configuration is enabled in the Fabric, then the
same configuration becomes enabled in the new switch. After this operation, the cfgShow
command displays the same output on all switches in the Fabric, including the new switch.