Ospf Lsa Types

Front 1

LSA Type 1

Back 1

Router LSA - Includes a list of directly attached link, identified by IP prefix assigned to link, and the RID of the originating router. Floods within area only, does not cross ABR.

Front 2

LSA Type 2

Back 2

Network LSA - Lists each of the attached routers that make up the transit network. Ethernet is an example where the DR makes the announcement. They never cross an area boundary.

Front 3

LSA Type 3

Back 3

Summary LSA - ABR sends type 3's which advertise any network owned by an area to the rest of the areas.

Front 4

LSA Type 4

Back 4

Summary LSA - Used only when ASBR exists and provides a route to it. The type 4 is learned by the ABR from the ASBR.

Front 5

LSA Type 5

Back 5

External LSA - Describe routes to networks outside the OSPF AS. Originated by the ASBR and are flooded to the entire autonomous system.

Front 6

LSA Type 6

Back 6

Specializd LSAs that are used in multicast OSPF applications.

Front 7

Allows ASBRs, an addendum to the OSPF RFC, uses special LSA type 7

Back 7

Not So Stubby Area NSSA

Front 8

Labeled area 0, all other areas connect to this area to exchange and route information. Some properties as standard OSPF area.

Back 8

Backbone area

Front 9

The area does not accept information about routes external to the AS, such as routes from non-OSPF sources. If routers need to route to networks outside the AS they use a default route. Cannot contain ASBRs

Back 9

Stub Area

Front 10

Does not accept external autonomous system routes or summary routes from other areas internal to the autonomous system. If the route needs to send a packet to a network external to the area, it sends the packet using a default route. Cannot contain ASBRs

Back 10

Totally Stubby Area