Which of the following is true about the OSPF Link-State Advertisement (LSA) types?

OSPF uses different types of Link-State Advertisements (LSAs) to describe the network topology. Type 1 LSAs, also known as Router LSAs, are fundamental to this process. Each router generates a Type 1 LSA to describe its own state, including its active links, the IP addresses of its interfaces, and the cost to its neighbors within a specific area. These LSAs are flooded only within the area in which they originate, providing the necessary information for all routers in that area to build an identical topological map.

B. Type 3 LSAs (Summary LSAs), not Type 2, are used by ABRs to advertise routes between different OSPF areas.

C. Type 5 LSAs (AS External LSAs), not Type 3, are used to advertise routes external to the OSPF autonomous system.

D. Type 2 LSAs (Network LSAs), not Type 4, are used by the Designated Router (DR) to advertise network information on a multi-access segment.

1. Juniper Networks. (2023). Junos OS Routing Protocols Library for Routing Devices. OSPF LSA Types. "Type 1 LSAs (Router LSAs)—Describe the state of the links of a router to an area. These LSAs are flooded only within the area in which they originate."

2. Moy

J. (1998). RFC 2328: OSPF Version 2. Section 12.4.1

"Router-LSAs". "Router-LSAs are the Type 1 LSAs. Each router in an area originates a router-LSA. The LSA describes the state and cost of the router's links (i.e.

interfaces) to the area."

3. Juniper Networks. (2023). Junos OS Routing Protocols Library for Routing Devices. Understanding OSPF LSA Types. Provides a table detailing the function of each LSA type

confirming Type 1 LSAs describe router links.