OSPF LSA Types
In this video, I only showed Router LSA, Network LSA, Summary LSA, Summary ASBR LSA, AS External LSA and I will make a separate with video for NSSA LSA.
OSPF LSA Types
LSA Types Overview:
LSA Type 1: Router LSA
LSA Type 2: Network LSA
LSA Type 3: Summary LSA
LSA Type 4: Summary ASBR LSA
LSA Type 5: Autonomous system external LSA
LSA Type 6: Multicast OSPF LSA
LSA Type 7: Not-so-stubby area LSA
LSA Type 8: External attribute LSA for BGP
LSA Types Summary:
Type 1 – Router LSA: The Router LSA is generated by each router for each area it is located. In the link-state ID you will find the originating router’s ID.
Type 2 – Network LSA: Network LSAs are generated by the DR. The link-state ID will be the interface IP address of the DR.
Type 3 – Summary LSA: The summary LSA is created by the ABR and flooded into other areas.
Type 4 – Summary ASBR LSA: Other routers need to know where to find the ASBR. This is why the ABR will generate a summary ASBR LSA which will include the router ID of the ASBR in the link-state ID field.
Type 5 – External LSA: also known as autonomous system external LSA: The external LSAs are generated by the ASBR.
Type 6 – Multicast LSA: Not supported and not used.
Type 7 – External LSA: also known as not-so-stubby-area (NSSA) LSA: As you can see area 2 is a NSSA (not-so-stubby-area) which doesn’t allow external LSAs (type 5). To overcome this issue we are generating type 7 LSAs instead.
CONFIGURATION:
R1:
conf t
router ospf 1
network 10.10.12.0 0.0.0.255 area 0
network 1.1.1.0 0.0.0.255 area 0
end
wr
conf t
interface loopback 1
ip address 11.11.11.11 255.255.255.0
!
router ospf 1
redistribute connected subnets
end
wr
R2:
conf t
router ospf 1
network 10.10.12.0 0.0.0.255 area 0
network 10.10.23.0 0.0.0.255 area 1
end
wr
R3:
conf t
router ospf 1
network 10.10.23.0 0.0.0.255 area 1
network 3.3.3.0 0.0.0.255 area 1
end
wr
VERIFICATION:
show run | sec ospf
show ip ospf neighbor
show ip ospf database
show ip route ospf
REFERENCES:
OSPF LSA Types Explained
https://networklessons.com/ospf/ospf-...
OSPF Design Guide
https://www.cisco.com/c/en/us/support...
OSPF LSA TYPES
https://learningnetwork.cisco.com/s/q...
OSPF LSA Types and Descriptions
https://learningnetwork.cisco.com/s/a...
#cisco #ccnp #ccie #ospf
