Review the Operation and Behavior OSPF POWERSWITCH-DATA-CENTER-DEPLOY Practice Questions (Page 5)

Questions 21–25

1. 21foundation · easy

   When an OSPF router detects a link state change, what is the immediate action it takes?

   • AIt recalculates the routing table using the existing LSDB without flooding any new information.
   • BIt waits for the next periodic update interval before propagating the change.
   • CIt floods a new LSA to its neighbors and then runs the SPF algorithm to recalculate routes.
   • DIt immediately sends a routing update to all routers in the autonomous system.
   Reveal Solution Discussion Select an answer first
2. 22expert · hard

   An OSPF router is in the Loading state with a neighbor. The router has sent a Link-State Request (LSR) for a specific LSA but has not received the corresponding Link-State Update (LSU). What will happen if the retransmit timer expires?

   • AThe router will flood the LSA to all other neighbors.
   • BThe router will resend the LSR for the missing LSA.
   • CThe router will declare the neighbor dead and restart the adjacency.
   • DThe router will transition back to the Exchange state.
   Reveal Solution Discussion Select an answer first
4. 23expert · hard

   An OSPF network experiences frequent route flapping due to a unstable link. The network engineer wants to reduce the impact of SPF recalculation on CPU usage. Which configuration change would best achieve this?

   • AIncrease the OSPF dead interval to keep adjacencies longer.
   • BChange the OSPF network type to broadcast on all interfaces.
   • CIncrease the OSPF SPF throttling timers to delay recalculation.
   • DDecrease the OSPF hello interval to detect failures faster.
   Reveal Solution Discussion Select an answer first
5. 24application · medium

   A link failure occurs on a point-to-point OSPF link between two routers. Which sequence of events best describes how OSPF converges?

   • AThe router immediately runs SPF without waiting for the dead timer, and then sends Hello packets to confirm the failure.
   • BThe router waits for the retransmit interval to expire, then sends a new DBD packet to the neighbor.
   • CThe router sends a Link-State Acknowledgment to the neighbor, which triggers an immediate SPF recalculation.
   • DThe neighbor is declared dead after the dead interval expires, the router floods LSUs about the failed link, and each router runs SPF to recalculate routes.
   Reveal Solution Discussion Select an answer first
6. 25foundation · easy

   In the OSPF neighbor state machine, which state indicates that a router has received a Hello packet from a neighbor but has not yet seen its own Router ID in the neighbor's Hello packet?

   • AInit
   • BExStart
   • C2-Way
   • DFull
   Reveal Solution Discussion Select an answer first