Users Guide

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.The system supports up to 16 OSPFv2 processes.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.
Processing SNMP and Sending SNMP Traps
Only the process in default vrf can process the SNMP requests and send SNMP traps.
NOTE: SNMP gets request corresponding to the OspfNbrOption field in the OspfNbrTable returns a value of 66.
RFC-2328 Compliant OSPF Flooding
In OSPF, flooding is the most resource-consuming task. The flooding algorithm described in RFC 2328 requires that OSPF
flood LSAs on all interfaces, as governed by LSA’s flooding scope (refer to Section 13 of the RFC.)
When multiple direct links connect two routers, the RFC 2328 flooding algorithm generates significant redundant information
across all links.
By default, Dell Networking OS implements an enhanced flooding procedure which dynamically and intelligently detects when
to optimize flooding. Wherever possible, the OSPF task attempts to reduce flooding overhead by selectively flooding on a
subset of the interfaces between two routers.
Enabling RFC-2328 Compliant OSPF Flooding
To enable OSPF flooding, use the following command.
When you enable this command, it configures Dell Networking OS to flood LSAs on all interfaces.
• Enable RFC 2328 flooding.
ROUTER OSPF mode
Open Shortest Path First (OSPFv2 and OSPFv3) 572