What is NSSA OSPF?
NSSA (Not so stubby area) is an OSPF area type that allows the injection of external routes into the stub area by using a special LSA type called LSA type 7. This LSA type 7 is converted into an LSA type 5 when it leaves the NSSA area.
What is stub in OSPF?
Stub area, also called stub area, the so-called stub area, means that the area does not accept any external routes of non-OSPF network, if it wants to reach those external routes, only Need to send it through the default route.
What are the types of OSPF?
LSA Type 5: Autonomous system external LSA. LSA Type 6: Multicast OSPF LSA….OSPF LSA Types Explained.
| Link Type | Description | Link ID |
|---|---|---|
| 1 | Point-to-point connection to another router. | Neighbor router ID |
| 2 | Connection to transit network. | IP address of DR |
| 3 | Connection to stub network. | IP Network |
| 4 | Virtual Link | Neighbor router ID |
What is normal area in OSPF?
Normal area This area connects to the AS backbone area through one or more ABRs (physically or through a virtual link) and supports type-3 summary LSAs and type-5 external link LSAs to and from the backbone area. ASBRs are allowed in normal areas.
What is the difference between stub area and NSSA?
An OSPF stub area has no external routes in it, so you cannot redistribute from another protocol into a stub area. A not-so-stubby area (NSSA) allows external routes to be flooded within the area. These routes are then leaked into other areas. However, external routes from other areas still do not enter the NSSA.
What is Type 5 LSA OSPF?
The type-5 LSA is the external LSA. As the name suggests, it describes networks that are external to the OSPF domain, injected into OSPF via some form of redistribution. When redistributing into OSPF, the routes can be of two types – E1 and E2 external routes.
What is stub and NSSA?
An NSSA is a bit like a stub as far as the internal OSPF topology is concerned, but it is allowed to connect to the outside world. In other words, it is allowed to have an ASBR border router. Imagine you had a branch office that had an external link, say, to the Internet.
Why we need stub area in OSPF?
To control the advertisement of external routes into an area, OSPF uses stub areas. By designating an area border router (ABR) interface to the area as a stub interface, you suppress external route advertisements through the ABR.
What are 4 router types in OSPF?
Within an OSPF area, routers are divided into the following categories.
- Internal Router. —A router with that has OSPF neighbor relationships only with devices in the same area.
- Area Border Router (ABR)
- Backbone Router.
- Autonomous System Boundary Router (ASBR)
What are the three categories of OSPF?
OSPF area types
- Type 1 – Represents a router.
- Type 2 – Represents the pseudonode (designated router) for a multiaccess link.
- Type 3 – A network link summary (internal route)
- Type 4 – Represents an ASBR.
- Type 5 – A route external to the OSPF domain.
- Type 7 – Used in stub areas in place of a type 5 LSA.
Why do we need AREA 0 in 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.
Why We Use Area in OSPF?
In OSPF, a single autonomous system (AS) can be divided into smaller groups called areas. This reduces the number of link-state advertisements (LSAs) and other OSPF overhead traffic sent on the network, and it reduces the size of the topology database that each router must maintain.