Cisco Certified Network Associate (CCNA) Practice Exam

Which LSA type is generated by the Designated Router (DR) in OSPF?

1. Type 1: Router LSA

2. Type 3: Summary LSA

3. Type 2: Network LSA

4. Type 5: External LSA

The correct answer is: Type 2: Network LSA

The correct answer identifies the LSA type that the Designated Router (DR) generates in Open Shortest Path First (OSPF). In OSPF, the DR is responsible for minimizing the amount of routing information exchanged within a network segment, primarily in broadcast and non-broadcast multiple access (NBMA) networks. The Network LSA, which is of Type 2, is generated by the DR and contains information about the routers that are part of the broadcast or multi-access network. This LSA describes the shared network and lists all the routers attached to it. By consolidating this information, the DR reduces the overall amount of routing information sent through the network, which helps maintain efficient routing and minimizes overhead. To clarify the context of the other LSA types: Type 1 (Router LSA) is generated by each router and contains information about the router itself and its directly connected links. Type 3 (Summary LSA) is generated by area border routers and is used to summarize routes between different OSPF areas. Type 5 (External LSA) is used to advertise routes from other protocols into OSPF, which is exclusively generated by the ASBR (Autonomous System Boundary Router). These LSAs serve different purposes,