Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.14.1.0 - Page 645

Enabling Fast-Convergence The fast-convergence CLI sets the minimum origination and arrival LSA parameters to zero (0), allowing rapid route calculation. When you disable fast-convergence, origination and arrival LSA parameters are set to 5 seconds and 1 second, 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 fast-convergence parameter setting allows for even finer tuning of the convergence speed. The higher the number, the faster the convergence. To enable or disable fast-convergence, use the following command. • Enable OSPF fast-convergence and specify the convergence level. CONFIG-ROUTEROSPF- id mode fast-convergence {number} The parameter range is from 1 to 4. The higher the number, the faster the convergence. When disabled, the parameter is set at 0. NOTE: A higher convergence level can result in occasional loss of OSPF adjacency. Generally, convergence level 1 meets most convergence requirements. Only select higher convergence levels following consultation with Dell Technical Support. Examples of the fast-converge Command In the following examples, Convergence Level shows the fast-converge parameter setting and Min LSA origination shows the LSA parameters (shown in bold). DellEMC(conf-router_ospf-1)#fast-converge 2 DellEMC(conf-router_ospf-1)#ex DellEMC(conf)#ex DellEMC#show ip ospf 1 Routing Process ospf 1 with ID 192.168.67.2 Supports only single TOS (TOS0) routes SPF schedule delay 5 secs, Hold time between two SPFs 10 secs Convergence Level 2 Min LSA origination 0 secs, Min LSA arrival 0 secs Number of area in this router is 0, normal 0 stub 0 nssa 0 DellEMC# The following examples shows how to disable fast-convergence. DellEMC#(conf-router_ospf-1)#no fast-converge DellEMC#(conf-router_ospf-1)#ex DellEMC#(conf)#ex DellEMC##show ip ospf 1 Routing Process ospf 1 with ID 192.168.67.2 Supports only single TOS (TOS0) routes SPF schedule delay 5 secs, Hold time between two SPFs 10 secs Convergence Level 0 Min LSA origination 5 secs, Min LSA arrival 1 secs Number of area in this router is 0, normal 0 stub 0 nssa 0 DellEMC# Changing OSPFv2 Parameters on Interfaces In Dell EMC Networking OS, you can modify the OSPF settings on the interfaces. Some interface parameter values must be consistent across all interfaces to avoid routing errors. For example, set the same time interval for the hello packets on all routers in the OSPF network to prevent misconfiguration of OSPF neighbors. Open Shortest Path First (OSPFv2 and OSPFv3) 645