Cisco Certified Network Associate (CCNA) Practice Exam

What LSA is generated by the DR responsible for its subnet?

1. Type 1 LSA (Router LSA)

2. Type 2 LSA (Network LSA)

3. Type 3 LSA (Inter-Area Prefix LSA)

4. Type 5 LSA (AS External LSA)

The correct answer is: Type 2 LSA (Network LSA)

The correct answer is that the Designated Router (DR) generates a Type 2 LSA, also known as a Network LSA. In OSPF (Open Shortest Path First), the DR is responsible for representing a multi-access network segment, such as an Ethernet LAN. The Network LSA is created by the DR to summarize the information about the routers attached to that specific multicast network segment. This type of LSA includes the list of all routers that are part of the multi-access network and covers the subnet it resides on. It essentially helps OSPF in managing the complex topologies commonly found in networks with many devices connected to the same local segment, ensuring efficient routing updates across the OSPF domain. The other types of LSAs serve different purposes and are generated by different elements within OSPF. For instance, Type 1 LSAs are created by each router to describe the router's own interfaces and their states, not specifically for a subnet like the Type 2 LSA does. Type 3 LSAs, known as Inter-Area Prefix LSAs, are used to summarize routes between different OSPF areas, while Type 5 LSAs, or AS External LSAs, are used to describe routes to external