OSPFv2 supports helper-only and restarting-only roles. By default, both helper and restarting roles areenabled. OSPFv2 supports the helper-reject role globally on a router.OSPFv3 supports helper-only and restarting-only roles. The helper-only role is enabled by default. Toenable the restarting role in addition to the helper-only role, configure a grace period. ReconfigureOSPFv3 graceful restart to a restarting-only role when you enable the helper-reject role on aninterface. OSPFv3 supports the helper-reject role on a per-interface basis.Configuring helper-reject role on an OSPFv2 router or OSPFv3 interface enables the restarting-onlyrole globally on the router or locally on the interface. In a helper-reject role, OSPF does notparticipate in the graceful restart of an adjacent OSPFv2/v3 router.If multiple OSPF interfaces provide communication between two routers, after you configure helper-reject on one interface, all other interfaces between the two routers behave as if they are in the help-reject role.• OSPFv2 and OSPFv3 support planned-only and/or unplanned-only restarts. The default is support forboth planned and unplanned restarts.A planned restart occurs when you enter the redundancy force-failover rpm command toforce the primary RPM to switch to the backup RPM. During a planned restart, OSPF sends out aGrace LSA before the system switches over to the backup RPM.An unplanned restart occurs when an unplanned event causes the active RPM to switch to the backupRPM, such as when an active process crashes, the active RPM is removed, or a power failure happens.During an unplanned restart, OSPF sends out a Grace LSA when the backup RPM comes online.To display the configuration values for OSPF graceful restart, enter the show run ospf command forOSPFv2 and the show run ospf and show ipv6 ospf database database-summary commandsfor OSPFv3.Fast Convergence (OSPFv2, IPv4 Only)Fast convergence allows you to define the speeds at which LSAs are originated and accepted, and reduceOSPFv2 end-to-end convergence time.Dell Networking OS allows you to accept and originate LSAa as soon as they are available to speed uproute information propagation.NOTE: The faster the convergence, the more frequent the route calculations and updates. Thisimpacts CPU utilization and may impact adjacency stability in larger topologies.Multi-Process OSPFv2 (IPv4 only)Multi-process OSPF is supported on the Z9000 platform with Dell Networking OS version 7.8.1.0 andlater, and is supported on OSPFv2 with IPv4 only.Multi-process OSPF allows multiple OSPFv2 processes on a single router. Multiple OSPFv2 processesallow for isolating routing domains, supporting multiple route policies and priorities in different domains,and creating smaller domains for easier management.The Z9000 supports up to 32 OSPFv2 processes.Each OSPFv2 process has a unique process ID and must have an associated router ID. There must be anequal number of interfaces and must be in Layer-3 mode for the number of processes created. ForOpen Shortest Path First (OSPFv2 and OSPFv3) 551
