What is a OSPF stub area?

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. This area supports 1, 2, and 3 LSAs.

Where is OSPF stub area set?

To configure OSPF stub areas:

  • On all routing devices in the area, configure an OSPF stub area.
  • On the ABR, inject a default route into the area.
  • (Optional) On the ABR, restrict summary LSAs from entering the area.
  • If you are done configuring the devices, commit the configuration.

How do I set up a stub area?

Enable OSPF on all routers, and split the AS into three areas. Configure Router A and Router B as ABRs to forward routing information between areas. Configure Router D as the ASBR to redistribute static routes. Configure Area 1 as a stub area to reduce advertised LSAs without influencing reachability.

Why do we need stub area?

Stub Areas This ensures that routers in the stub area will be able to route traffic to external destinations without having to maintain all of the individual external routes. Because external routes are not received by the stub area, ABRs also do not forward type 4 LSAs from other areas into the stub.

What is totally stub area?

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. 0.0/0 is originated into the stub area by an ABR, so that devices in the area can forward all traffic for which a specific route is not known, via ABR.

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.

What is stub area network?

A stub network, or pocket network, is a somewhat casual term describing a computer network, or part of an internetwork, with no knowledge of other networks, that will typically send much or all of its non-local traffic out via a single path, with the network aware only of a default route to non-local destinations.

What is a Type 3 LSA?

The Summary (Type 3) LSA is used for advertising prefixes learned from the Type 1 and Type 2 LSAs into a different area. The Area Border Router (ABR) is the OSPF device that separates areas and it is this device that advertises the Type 3 LSA.

Why we configure 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.

Is OSPF Layer 2?

OSPF uses Mulitcast IP address 224.0. 0.5 add 224.0. 0.6, as long as they’re allowed you should be good, they are of course Layer 3.

What is a totally stubby area in OSPF?

Stub areas are shielded from external routes but receive information about networks that belong to other areas of the same OSPF domain . You can define totally stubby areas. Routers in totally stubby areas keep their LSDB-only information about routing within their area, plus the default route.

What is OSPF totally stubby area?

An OSPF totally stubby area is one which only has a default route to the rest of the OSPF routing domain. Such an area may have more than one router, but these routers will only know about the default route to the outside. A stub autonomous system that is connected to only one other autonomous system,…

What are different area types used in the OSPF?

What are the OSPF Area Types? Standart Area. This Area is the normal Area of OSPF. Backbone Area (Area 0) Backbone Area (Area 0) is the central of OSPF Network and all the other Areas are connected to thsese Backbone Area. Stub Area. Stub Area is the first specific Area. Totally Stubby Area. Totally Stubby Area is one step more strict Area than Stub Area.

What is the use of areas in OSPF?

OSPF uses areas to simplify administration and optimize traffic and resource utilization . An area is simply a logical grouping of contiguous networks and routers.