Interoperability With Legacy Fcr Switches; Backward Compatibility Support; Front Domain Consolidation; Using Front Domain Consolidation - HP A7533A - Brocade 4Gb SAN Switch Base Administrator's Manual

If you replace an 8-Gbps port blade with another 8-Gbps port blade, the EX_Port configuration remains
the same.

Interoperability with legacy FCR switches

A legacy FCR switch is a switch running Fabric OS 5.1. or earlier or XPath OS.
The following interoperability considerations apply when administering legacy FCR switches in the same
backbone fabric as switches supporting Fabric OS 5.2.0 or later:
• When a legacy switch is connected to the backbone fabric, a RASLog message is issued indicating that
the capability of the backbone fabric is lower because legacy FCR switches support lower capability
limits.
• If an XPath OS switch joins the backbone fabric, a RASLog message is issued indicating that the
backbone-to-edge fabric is not supported with the XPath OS switch.
For further information on these RASLog messages, see the FCR chapter in the Fabric OS Message
Reference.

Backward compatibility support

For backward compatibility, FCR that supports EX_Port trunking can continue to interoperate with older
FCR switches and all previously supported HP switches in the edge fabric.

Front domain consolidation

The FCR switch is connected to the edge fabrics using EX_Ports or VEX_Ports. On prior FCR releases (XPath
7.1.2, 7.3, 7.4 and Fabric OS 5.1) every EX_Port connecting to an edge fabric projects its own front
domain. For example, if there are three EX_Ports connected from the router to the edge fabric, there will be
three front domains projected to the edge fabric.
The Front Domain Consolidation is when one front domain from a single FCR is projected to the edge
fabric regardless of the number of EX_Ports connected from that router to the edge fabric. The front domain
is consolidated only within the FCR switch. Another router connected to the same edge fabric projects a
different front domain.
Front domain consolidation conserves resources on the FCR switch. Expanded use of FCR switches with
multiple EX_Ports connected to the same edge fabric raises the overhead of projecting a front domain for
each EX_Port and quickly uses up resources within the edge fabric and resource consumption on the FC
router.
In releases prior to 5.2.0, every EX_Port connected to the same edge fabric had a unique domain and
unique domains require separate WWNs. With front domain consolidation, the domain is the same for all
ports connected to the same edge fabric from the FC router, so in this case the WWN will be the same.

Using front domain consolidation

To support the consolidated front domain feature, existing CLI and API commands are used to manage and
configure the router. Existing CLI commands offer additional options to support the front domain
consolidation feature.
The portCfgExport command has additional options to verify the front Domain ID. The
portCfgExport –d option is changed to enforce use of the same front Domain ID for the EX_Ports
connected to the same edge fabric. The portCfgExport display results remain the same.
For more information about the portCfgExport -d option, see the command details in the Fabric OS
Command Reference.
340 Using the FC-FC routing service