OSPF Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

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OSPF Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

Configure OSPF SPF scheduling and prefix prioritization

Updated: June 26, 2026

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Configure OSPF SPF scheduling and prefix prioritization to optimize route convergence.

Use this task to adjust OSPFv2 and OSPFv3 SPF calculation intervals and prioritize specific prefixes when calculating routes, reducing convergence times during network changes.

Optimize OSPF convergence and ensure critical prefixes receive higher priority during SPF calculations.

Before you begin

  • Ensure you have configuration privileges.

  • Verify that OSPF addressing, routing policy, and interface planning are complete.

Follow these steps to configure and verify OSPF areas and neighbours:

Procedure

  1. Configure OSPF SPF scheduling intervals.

    • Enter global configuration mode and OSPF process configuration.

    • Set the OSPF router ID.

    • Configure SPF throttle timers to specify calculation delays.

    Example:

    
Router# configure
Router(config)# router ospf 1
Router(config-ospf)# router-id 192.168.4.3
Router(config-ospf)# timers throttle spf 10 4800 90000
Router(config-ospf)# area 0
Router(config-ospf-ar)# interface GigabitEthernet 0/1/0/3

  2. Configure prefix prioritization for critical OSPF prefixes.

    • Define a prefix-set for critical prefixes.

    • Create a route-policy to assign high SPF priority to these prefixes.

    • Apply the route-policy to OSPF SPF prefix prioritization.

    Example:

    
Router# configure
Router(config)# prefix-set ospf-critical-prefixes
Router(config-pfx)# 66.0.0.0/16
Router(config-pfx)# end-set
Router# route-policy ospf-spf-priority
Router(config-rpl)# if destination in ospf-critical-prefixes then
   set spf-priority critical
endif
Router(config-rpl)# end-policy
Router# router ospf 1
Router(config-ospf)# spf prefix-priority route-policy ospf-spf-priority
Router(config-ospf)# commit

  3. Verify SPF prefix prioritization configuration.

    Check the prefix-set and route-policy configuration reflects the intended critical prefixes.

    Example:

    
Router# show rpl route-policy ospf-spf-priority detail
prefix-set ospf-critical-prefixes
    66.0.0.0/16
end-set
!
route-policy ospf-spf-priority
    if destination in ospf-critical-prefixes then
    set spf-priority critical
    endif
end-policy
!

The OSPF configuration is committed and the router operational state reflects optimized SPF scheduling and prioritized critical prefixes.

What to do next

Continue with related OSPF verification or perform further tuning tasks as needed for your deployment workflow.