What is OSPF stub area?

What is OSPF stub area?

An OSPF stub area is an area that does not permit flooding of AS external link state advertisements. It only receives routing information for destinations within the same stub area and for destinations in other areas within the OSPF domain.

What is the difference between backbone area and stub area in OSPF?

The backbone is considered a standard area. Stub areas can contain type 1, 2, and 3 LSAs. A default route is substituted for external routes. Totally stubby areas can only contain type 1 and 2 LSAs, and a single type 3 LSA.

What is difference between NSSA and totally NSSA?

Difference between NSSA/Totally NSSA and Stubby/Totally Areas is; NSSAs redistribute external routes(Type-7 LSA) into the Area., Stubbys don’t. NSSA was created because Stubby areas block all Type-5 external LSAs. So Stubby Area can not learn any external LSAs. NSSA lets stub area to learn external Areas(Type-7 LSAs).

What is the purpose of a stub area?

A stub area disables advertisements of external routes. By default, the ABR sends summary LSAs (type 3 LSAs) into stub areas. You can further reduce the number of LSAs sent into a stub area by configuring the device to stop sending type 3 LSAs into the area.

What is the difference between stub and totally stub area?

A stub area is an area in which advertisements of external routes are not allowed, reducing the size of the database. A totally stubby area (TSA) is a stub area in which summary link-state advertisement (type 3 LSAs) are not sent. A default summary LSA, with a prefix of 0.0.

What is the difference between stub and totally stubby area?

A stub area is an area in which advertisements of external routes are not allowed, reducing the size of the database. A totally stubby area (TSA) is a stub area in which summary link-state advertisement (type 3 LSAs) are not sent.

What is totally NSSA?

Totally Not So Stubby Area (NSSA) Totally Not So Stubby Area is like Not So Stubby Area except one diffference. In Totally NSSA, Summary LSAs(Type 3 and Type 4) are also not accepted. It get these with only one default route.

Why do we need NSSA in OSPF?

NSSA is an OSPF Stub Area, which can carry routes learned by other protocols such as BGP or RIP. Allows the import of external routes in a limited fashion using Type-7 LSAs. NSSA border routers translate selected Type 7 LSAs into Type 5 LSAs, which can then be flooded to all Type-5 capable areas.

What type of LSA is blocked in totally NSSA area?

Totally NSSA (totally not so stubby area) If you configure an area as stub it will block all type 5 external LSAs.

What is difference between ABR and Asbr?

Area border router (ABR) A router that connects one or more areas to the OSPF backbone. Autonomous system border router (ASBR) A router that is connected to one or more logical entities (AS), usually through an exterior routing protocol such as BGP.

What is difference between OSPF adjacency and neighbor?

I’m under the impression that OSPF neighbors are routers that are in the same area and that is running OSPF. An OSPF adjacency is formed when OSPF neighbors exchange routing updates. My example of this is an environment of 3 OSPF routers. There would be one DR, one BDR, and one DROTHER router.

What is backbone router in OSPF?

Backbone router is a router that has an interface assigned to area 0. More specific – all ABRs and all internal routers (routers that have all interfaces in area 0) connected to area 0 are considered backbone routers.