Dell N1100-ON, Reference Manual

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Layer 3 Routing Commands
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OSPF Commands
Dell EMC Networking N3000/N3100/N4000 Series Switches
The Dell Network N1500/N2000/N2100-ON series support limited routing and
multicast capabilities. See the Users Configuration Guide section “Feature
Limitations and Platform Constants” for supported capabilities.
OSPF is a link-state protocol. Dell EMC Networking OSPF supports variable-
length subnet masks. Dell EMC Networking OSPF only operates over VLAN
interfaces.
OSPF operates within a hierarchy. The largest entity within the hierarchy is
the autonomous system (AS), a collection of networks under a common
administration sharing a common routing strategy. This is sometimes called a
routing domain. An AS can be divided into a number of areas or groups of
contiguous networks and attached hosts. Routers within the same area share
the same information, so they have identical topological databases.
Information is sent in the form of link-state advertisements (LSAs) to all
other routers within the same hierarchical area. An area's topology is not
visible to routers outside the area.
Two different types of OSPF routing occur as a result of area partitioning:
Intra-area and Inter-area. Intra-area routing occurs if a source and destination
are in the same area. Inter-area routing occurs when a source and destination
are in different areas. An OSPF backbone distributes information between
areas.
For IPv4 networks, Dell EMC Networking routing supports OSPF version 2 in
accordance with RFC 2328. The Dell EMC Networking routing also provides
a compatibility mode for the RFC 1583 OSPF specification, which allows
interoperability with OSPF version 2 routers using the older implementation.
The Dell EMC Networking OSFPv2 implementation supports point-to-point
operation on Ethernet interfaces. The user can configure an OSPFv2
interface to run in broadcast or point-to-point mode. When there are only
two routers attached to the link, OSPFv2 point-to-point mode has the
advantage of not requiring designated router election or origination of a
network LSA for the LAN. This makes the protocol more efficient. Dell EMC
Networking also supports OSPFv3 for use with IPv6 networks.
The Dell EMC Networking routing OSPF NSSA feature supports RFC 3101,
The OSPF Not-So-Stubby Area (NSSA) Option.