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

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18-3
Nexus 5000 Series Switch Fabric Manager Software Configuration Guide
OL-16598-01
Chapter 18 Configuring Fibre Channel Routing Services and Protocols
FSPF Global Configuration
Figure 18-2 Fault Tolerant Fabric with Redundant Links
For example, if all links are of equal speed and no SAN port channels exist, the FSPF calculates four
equal paths from A to C: A1-E-C, A2-E-C, A3-D-C, and A4-D-C. If SAN port channels exist, these paths
are reduced to two.
FSPF Global Configuration
By default, FSPF is enabled on switches in the Nexus 5000 Series.
Some FSPF features can be globally configured in each VSAN. By configuring a feature for the entire
VSAN, you do not have to specify the VSAN number for every command. This global configuration
feature also reduces the chance of typing errors or other minor configuration errors.
Note FSPF is enabled by default. Generally, you do not need to configure these advanced features.
Caution The default for the backbone region is 0 (zero). You do not need to change this setting unless your region
is different from the default. If you are operating with other vendors using the backbone region, you can
change this default to be compatible with those settings.
This section includes the following topics:
• About SPF Computational Hold Times, page 18-3
• About Link State Records, page 18-3
• Configuring FSPF on a VSAN, page 18-4
• Resetting FSPF to the Default Configuration, page 18-5
• Enabling or Disabling FSPF, page 18-5
About SPF Computational Hold Times
The SPF computational hold time sets the minimum time between two consecutive SPF computations
on the VSAN. Setting this to a small value means that FSPF reacts faster to any fabric changes by
recomputing paths on the VSAN. A small SPF computational hold time uses more switch CPU time.
About Link State Records
Each time a new switch enters the fabric, a link state record (LSR) is sent to the neighboring switches,
and then flooded throughout the fabric.
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