Contents
What is the purpose of NSSA area?
Not-so-stubby areas (NSSAs) are an extension of OSPF stub areas. Like stub areas, they prevent the flooding of AS-external link-state advertisements (LSAs) into NSSAs and instead rely on default routing to external destinations. As a result, NSSAs (like stub areas) must be placed at the edge of an OSPF routing domain.
What is NSSA area in OSPF?
The OSPFv2 not-so-stubby area (NSSA) enables you to configure OSPFv2 areas that provide the benefits of stub areas, but that also are capable of importing external route information. This example shows two routing domains, a BGP domain and an OSPF domain. …
Why do we need backbone area in OSPF?
Backbone Area The backbone area forms the central hub of an OSPF network. All other areas are connected to it, and inter-area routing happens via routers connected to the backbone area and to their own non-backbone areas. The backbone area distributes all routing information between the non-backbone areas.
Do you need Area 0 OSPF?
Albeit OSPF is a link state protocol, the way OSPF handles inter-area traffic leaves it prone to routing loops. This is why OSPF must connect back to area 0 – to avoid routing loops.
How is NSSA boundary router propagated into OSPF?
An NSSA autonomous system boundary router (ASBR) generates this LSA and an NSSA area border router (ABR) translates it into a type 5 LSA, which gets propagated into the OSPF domain. The network diagram demonstrates this principle. Refer to this network diagram as you use this document: In the network diagram, Area 1 is defined as a stub area.
What’s the difference between OSPF stub area and NSSA?
A simple protocol such as RIP was usually run and handled the redistribution. With NSSA, you can extend OSPF to cover the remote connection by defining the area between the corporate router and the remote router as an NSSA. As with OSPF stub areas, NSSA areas cannot be injected with distributed routes via Type 5 LSAs.
Can a NSSA area be injected with distributed routes?
As with OSPF stub areas, NSSA areas cannot be injected with distributed routes via Type 5 LSAs. Route redistribution into an NSSA area is possible only with a special type of LSA that is known as Type 7 that can exist only in an NSSA area.
What are the different administrative distances in OSPF?
OSPF uses three different administrative distances: intra-area, interarea, and external. Routes within an area are intra-area; routes to another area are interarea; and routes from another routing domain learned via redistribution are external. The default distance for each type of route is 110.