Dell S4048T, Configuration Manual

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Configuring helper-reject role on an OSPFv2 router or OSPFv3 interface enables the restarting-only role
globally on the router or locally on the interface. In a helper-reject role, OSPF does not participate 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 for
both planned and unplanned restarts.
A planned restart occurs when you enter the
redundancy force-failover rpm
command to force
the primary RPM to switch to the backup RPM. During a planned restart, OSPF sends out a Grace 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 backup
RPM, 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 for
OSPFv2 and the
show run ospf
and
show ipv6 ospf database database-summary
commands for
OSPFv3.
Fast Convergence (OSPFv2, IPv4 Only)
Fast convergence allows you to define the speeds at which LSAs are originated and accepted, and reduce
OSPFv2 end-to-end convergence time.
Dell Networking OS allows you to accept and originate LSAs as soon as they are available to speed up route
information propagation.
NOTE: The faster the convergence, the more frequent the route calculations and updates. This impacts
CPU utilization and may impact adjacency stability in larger topologies.
Multi-Process OSPFv2 with VRF
Multi-process OSPF with VRF is supported on the Dell Networking OS. Only one OSPFv2 process per VRF is
supported.
Multi-process OSPF allows multiple OSPFv2 processes on a single router. Multiple OSPFv2 processes allow
for isolating routing domains, supporting multiple route policies and priorities in different domains, and
creating smaller domains for easier management.Each OSPFv2 process has a unique process ID and must
have an associated router ID. There must be an equal number of interfaces and must be in Layer-3 mode for
the number of processes created. For example, if you create five OSPFv2 processes on a system, there must
be at least five interfaces assigned in Layer 3 mode. Each OSPFv2 process is independent. If one process loses
adjacency, the other processes continue to function.
Open Shortest Path First (OSPFv2 and OSPFv3) 717