How many Link-State Advertisements (LSAs) are there in OSPF?

• A. 8
• B. 9
• C. 10
• D. 11

Answer: (D)

OSPF organizes topology data into distinct advertisements, with each LSA type carrying specific information needed to build the network map. There are five fundamental types that describe routers, networks, and inter-area routes, plus a reserved type that isn’t used in practice, a NSSA-specific type, and four opaque types reserved for future extensions. When you include every defined category—the five standard types, the reserved type, the NSSA type, and the four opaque types—you get eleven different LSA types in total.