OSPF offers special area types to reduce LSA flooding:
Stub Area: Blocks Type external LSAs. ABR injects a default route instead. Routers don't need to know every external destination.
Totally Stubby Area: Blocks Types , , and . Only default route and intra-area routes exist. Even smaller tables.
Not-So-Stubby Area (NSSA): Like stub, but allows local redistribution. Uses Type LSAs for local external routes, converted to Type at the ABR.
Use stub areas for branches that only need a default route to reach the core. This significantly reduces memory usage on branch routers.