Fspf Examples; Fault Tolerant Fabric Example; Redundant Link Example - Cisco Nexus 5000 Series Configuration Manual

Information About FSPF
• Uses a topology database to keep track of the state of the links on all switches in the fabric and associates
a cost with each link.
• Guarantees a fast reconvergence time in case of a topology change. Uses the standard Dijkstra algorithm,
but there is a static dynamic option for a more robust, efficient, and incremental Dijkstra algorithm. The
reconvergence time is fast and efficient as the route computation is done on a per VSAN basis.
The FSPF feature can be used on any topology.
Note

FSPF Examples

Fault Tolerant Fabric Example

The following figure depicts a fault tolerant fabric using a partial mesh topology. If a link goes down anywhere
in the fabric, any switch can still communicate with all others in the fabric. In the same way, if any switch
goes down, the connectivity of the rest of the fabric is preserved.
Figure 26: Fault Tolerant Fabric
For example, if all links are of equal speed, the FSPF calculates two equal paths from A to C: A-D-C (green)
and A-E-C (blue).

Redundant Link Example

To improve on the topology, each connection between any pair of switches can be replicated; two or more
links can be present between a pair of switches. The following figure shows this arrangement. Because switches
in the Cisco Nexus 5000 Series support SAN port channels, each pair of physical links can appear to the FSPF
protocol as one single logical link.
By bundling pairs of physical links, FSPF efficiency is considerably improved by the reduced database size
and the frequency of link updates. Once physical links are aggregated, failures are not attached to a single
link but to the entire SAN port channel. This configuration also improves the resiliency of the network. The
Cisco Nexus 5000 Series NX-OS SAN Switching Configuration Guide
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Configuring Fibre Channel Routing Services and Protocols
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