FCoE Cookbook for HP Virtual Connect Version 4.20 Firmware Enhancements May 2014

Benefits

This scenario can be used to simplify third-party interoperability concerns in environment where different types of Fibre

Channel switches are used (i.e. when connecting Nexus 5xxx to a non-Cisco Fibre Channel switch like a Brocade SAN

switch) because in NPV mode, the switch does not participate in domain operations or perform local switching. This

enables multivendor topologies to be implemented without the restrictions the FCF mode requires.

Additionally the NPV mode increases the SAN scalability as you can add switches to the faric without adding more

domain IDs but the number of ports to the fabric are increased.

In NPV mode, fabric logins are passed upstream from the edge switch to the core Brocade switch. The Nexus acts as a

pass through switch and converts the Fabric Login (FLOGI) command to a Fabric Discovery (FDISC) command and passes

it to the upstream SAN switch.

The use of multiple FCoE uplink ports on each VC module connected to Nexus allows dynamically distribution of the FCoE

traffic across the ports using a round robin format.

By providing ability to define multiple FCoE VLANs on a single set of uplinks, VC allows multi-VSAN capability to be

enabled on Nexus switches. The use of VSANs is fully transparent to the Brocade Core switches since Brocade has no

concept of VSANs, however VSANs can help to maintain separation and traffic isolation to the servers on the NPV

switches since zoning is not supported. On the Brocade side, zoning can be set to “extend” those VSANs to defined

Brocade zones that are connected to different storage targets.

Considerations

In NPV mode, the switch does not operate as a typical Fibre Channel switch, fabric services (i.e. Name Service, Fabric

Login, zoning, etc.) are not available and Fibre Channel switching is not performed: all traffic is switched upstream in the

core switch.

The NPV mode uses N Port ID Virtualization (NPIV) technology, F_Ports that normally connect to the fabric are

configured in this mode as NP_Ports and use NPIV to register multiple WWPNs to the F_Port on the other end.

Note: To convert a switch into NPV mode, you set the NPV feature to enable. This configuration command automatically

triggers a switch reboot and the system configuration is erased. You cannot configure NPV mode on a per-interface

basis. NPV mode applies to the entire switch.

For more information about the NPV Mode and Cisco support, see

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/configuration/guide/cli/npv.html

Multiple VSAN support

The number of FCoE networks per Shared Uplink Set is limited to 32. VSAN tagging is not supported for native FC fabrics.

The number of FCoE networks is additionally limited by the 1000 network domain limit.

For this feature to successfully integrate with Cisco Nexus switches it is important to note that for each FCoE VLAN a

unique FC VSAN must be created and association between the two must be strictly configured as 1-to-1. Mapping of a

single VLAN into multiple VSANs is not supported. This requirement is documented in Cisco’s best practice

recommendations.

All of the FCoE networks will share the same lossless Priority Flow Control (PFC) queue on any specific shared uplink set.

Sharing PFC queue between multiple VSANs will make it possible that traffic from one VSAN may have impact on traffic

from other VSANs. For that reason, it is highly recommended to create enough SAN subscription (i.e. by using a suitable

number of uplink between VC and Nexus but also between Nexus and Cisco MDS) to avoid any over-subscription issues

that would prevent SAN to pause and therefore to impact other VSANs. Therefore the use of multiple NP Ports between

the Nexus and Brocade Core switches is highly recommended.