Who made it?
A router, a DR, an ABR or an ASBR gives you the first clue.
Six LSA types. Zero panic.
See who originates each LSA, what it describes and how far it travels. Then open any type for the simple version, the technical version and the meme-worthy version.
How to read this
Every LSA answers a question.
OSPF routers build the same map from different kinds of information. The trick is to ask who created the LSA and what part of the map it describes.
Inside an area Between areas External routes
1Router LSAWho I am and what I can reachSoon
2Network LSAThe DR speaks for the segmentSoon
3Summary LSARoutes crossing an area borderSoon
4ASBR Summary LSAHow to find the ASBRSoon
5External LSARoutes from outside OSPFSoon
7NSSA External LSAExternal routes, NSSA editionSoon
Before you memorise anything
Follow the scope.
What is inside?
Links, a shared network, an area route or something external.
Where can it go?
Flooding scope tells you who needs this piece of the map.