OSPF LSA TYPES EXPLAINED! BEST HIGHLIGHTS. Learn Briefly clear and useful with picture

Have you ever wondered what is is the function of each of all the OSPF LSAs?


How it works? 
To master OSPF you should go straight to the OSPF LSA types. this is a brief and clear introduction of LSA OSPF types you must know before getting deeply on each specific type.
 Let's start with the first one:

LSA type 1  Router  Each router creates its own Type 1 LSA to represent itself for each area to which it connects. The LSDB for one area contains one Type 1 LSA per router per area, listing the RID and all interface IP addresses on that router that are in that area. Represents stub networks as well.


LSA type 2  Network  One per transit network. Created by the DR on the subnet, and represents the subnet and the router interfaces connected to the subnet.

LSA type 3  Net Summary  Created by ABRs to represent subnets listed in one area’s type 1 and 2 LSAs when being advertised into another area. Defines the links (subnets) in the origin area, and cost, but no topology data.

LSA type 4  ASBR Summary  Like a type 3 LSA, except it advertises a host route used to reach an ASBR

LSA type 5  AS External  Created by ASBRs for external routes injected into OSPF.

LSA type 6  Group Membership  Defined for MOSPF; not supported by Cisco IOS.

LSA type 7  NSSA External  Created by ASBRs inside an NSSA area, instead of a type 5 LSA.

LSA type 8  External Attributes  Not implemented in Cisco routers.

LSA type 9 to 11  Opaque  Used as generic LSAs to allow for easy future extension of OSPF; for example, type 10 has been adapted for MPLS traffic engineering.

To get a better understanding of how different OSPF LSA TYPES work, this image will help you better: