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Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
OL-29284-01, Release 6.x
Chapter 7 Configuring N Port Virtualization
Guidelines and Limitations
• NPV devices can connect to multiple NPV core switches. In other words, different NP ports can be
connected to different NPV core switches.
• NPV supports NPIV-capable module servers (nested NPIV).
• Only F, NP, and SD ports are supported in NPV mode.
• In the case of servers that are booted over the SAN with NPV, if an NPV link failover occurs, servers
will lose access to their boot LUN temporarily.
• NPV switches do not recognize the BB_SCN configuration on the xNP ports because of
interoperability issues with the third-party core switches.
NPV Traffic Management Guidelines
When deploying NPV traffic management, follow these guidelines:
• Use NPV traffic management only when the automatic traffic engineering by the NPV device is not
sufficient for the network requirements.
• Do not configure traffic maps for all the servers. For non-configured servers, NPV will use
automatic traffic engineering.
• Configure the Persistent FC ID on the core switch. Traffic engineering directs the associated server
interface to external interfaces that lead to the same core switch. The server will be assigned the
same FC ID for every log in. This guideline is not applicable if a 91x4 switch is used as the core
switch.
• Server interfaces configured to a set of external interfaces cannot use any other available external
interfaces, even if the configured interfaces are not available.
• Do not configure disruptive load balancing because this involves moving a device from one external
interface to another interface. Moving the device between external interfaces requires NPV relogin
to the core switch through F port leading to traffic disruption.
• Link a set of servers to a core switch by configuring the server to a set of external interfaces that are
linked to the core switch.
DPVM Configuration Guidelines
When NPV is enabled, the following requirements must be met before you configure DPVM on the NPV
core switch:
• You must explicitly configure the WWN of the internal FLOGI in DPVM. If DPVM is configured
on the NPV core switch for an end device that is connected to the NPV device, then that end device
must be configured to be in the same VSAN. Logins from a device connected to an NPV device will
fail if the device is configured to be in a different VSAN. To avoid VSAN mismatches, ensure that
the internal FLOGI VSAN matches the port VSAN of the NP port.
• The first login from an NP port determines the VSAN of that port. If DPVM is configured for this
first login, which is the internal login of the NPV device, then the NPV core switch’s VSAN F port
is located in that VSAN. Otherwise, the port VSAN remains unchanged.
For details about DPVM configuration, see the Cisco MDS 9000 Family NX-OS Fabric Configuration
Guide.
