CREST Practitioner Security Analyst (CPSA) Practice

What does Link State Routing primarily use to maintain a network route database?

1. Periodic updates from each router

2. A central routing authority

3. Flooding routing information to all routers

4. Direct communication with end devices

The correct answer is: Flooding routing information to all routers

Link State Routing primarily maintains a network route database through the process of flooding routing information to all routers in the network. This method allows each router to share its knowledge of the network's topology by broadcasting information about its local connections and the state of its links. As a result, every router has a complete view of the network, enabling them to independently calculate the shortest path to any destination using algorithms like Dijkstra's. This approach is efficient for several reasons. By ensuring that all routers receive the same data, it minimizes inconsistencies and allows for better decision-making regarding route selection. Each router uses the information received to update its own routing table based on the overall network topology, facilitating rapid updates when changes occur. Periodic updates from each router would imply a less efficient and potentially inconsistent state of the routing information, as routers would only update their databases at set intervals rather than immediately upon changes. A central routing authority is not characteristic of Link State Routing, as it operates in a decentralized manner where each router contributes to and maintains the route database. Direct communication with end devices is not relevant to the process of routing as it pertains to the operation of networking protocols and the exchange of routing information among routers.