Cisco Nexus 5000 Series Switch Fabric Manager Software Configuration Guide, NX-OS 4.0 (OL-16598-01, June 2008)

CHAPTER
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12-1
Nexus 5000 Series Switch Fabric Manager Software Configuration Guide
OL-16598-01
12
Configuring N-Port Virtualization
N-port virtualization (NPV) reduces the number of Fibre Channel domain IDs used in a SAN fabric.
Edge switches operating in NPV mode do not join a fabric; they pass traffic between the NPV core switch
and the end devices, which eliminates the need for a unique domain ID in each edge switch.
This chapter includes the following sections:
• Information About NPV, page 12-1
• Guidelines and Limitations, page 12-4
• Configuring NPV, page 12-4
Information About NPV
Typically, Fibre Channel networks are deployed using a core-edge model with a large number of fabric
switches connected to core devices. However, as the number of ports in the fabric increases, the number
of switches deployed also increases, resulting in a dramatic increase in the number of domain IDs (the
maximum number supported in one SAN is 239). This challenge becomes even more difficult when a
large number of blade switches are deployed in a Fibre Channel network.
NPV solves the increase in the number of domain IDs by sharing the domain ID of the NPV core switch
among multiple NPV switches.
The NPV edge switch aggregates multiple locally connected N ports into one or more external NP links.
The edge switch appears as a host to the core Fibre Channel switch, and as a Fibre Channel switch to the
servers in the fabric switch or blade switch.
NPV reduces the need for additional ports on the core switch because multiple devices attach to the same
port on the NPV core switch.
Figure 12-1 shows an interface-level view of an NPV configuration.
In Nexus 5000 Series switches, physical Fibre Channel interfaces can be NP ports or F ports. Virtual
Fibre Channel interfaces can be F ports.