Dell EMC SmartFabric OS10 User Guide Release 10.5.0

Fast convergence sets the minimum origination and arrival LSA parameters to zero (0), allowing rapid route calculation. A higher convergence level can result in occasional loss of OSPF adjacency.

Convergence level 1 meets most convergence requirements. The higher the number, the faster the convergence, and the more frequent the route calculations and updates. This impacts CPU utilization and may impact adjacency stability in larger topologies.

When you disable fast-convergence, origination and arrival LSA parameters are set to 0 msec and 1000 msec, respectively. Setting the convergence parameter from 1 to 4 indicates the actual convergence level. Each convergence setting adjusts the LSA parameters to zero, but the convergence-level parameter changes the convergence speed. The higher the number, the faster the convergence.

• Enable OSPFv2 fast-convergence and enter the convergence level in ROUTER-OSPF mode, from 1 to 4.

  fast-converge convergence-level

Configure fast convergence

OS10(config)# router ospf 65535
OS10(conf-router-ospf-65535)# fast-converge 1

View fast convergence

OS10(conf-router-ospf-65535)# do show ip ospf

Routing Process ospf 65535 with ID 99.99.99.99
Supports only single TOS (TOS0) routes
It is an Autonomous System Border Router
It is an Area Border Router
It is Flooding according to RFC 2328
Convergence Level 1
Min LSA origination 0 msec, Min LSA arrival 0 msec
Min LSA hold time 0 msec, Max LSA wait time 0 msec
Number of area in this router is 3, normal 1 stub 1 nssa 1
   Area BACKBONE (0)
       Number of interface in this area is 1
       SPF algorithm executed 28 times
       Area ranges are
       
   Area  (2)
       Number of interface in this area is 1
       SPF algorithm executed 28 times
       Area ranges are
       
   Area  (3)
       Number of interface in this area is 1
       SPF algorithm executed 28 times
       Area ranges are

Disable fast convergence

OS10(conf-router-ospf-65535)# no fast-converge