An enterprise router operating OSPF receives a Link-State Update (LSU) containing a revised Link-State Advertisement (LSA). Place the operational steps the router performs to process this update and adjust its routing table into the correct chronological order.
- 1Receive the Link-State Update (LSU) packet on an active OSPF-enabled interface.
- 2Verify the checksum and compare the LSA sequence number against the existing Link-State Database (LSDB) entry.
- 3Update the LSDB and flood the LSA out all active OSPF interfaces except the receiving interface.
- 4Execute the Dijkstra Shortest Path First (SPF) algorithm using the updated LSDB topology map.
- 5Install the newly calculated optimal paths and next hops into the Routing Information Base (RIB).
Answer
The correct sequence begins with receiving the LSU packet, verifying the LSA sequence number, updating the LSDB while flooding the LSA, running the Dijkstra SPF algorithm, and installing the recalculated best routes into the RIB.
When an OSPF router receives an LSU, it must first inspect the LSA for validity and compare its sequence number against the existing database. Once validated, the router updates its LSDB and immediately floods the LSA out other active OSPF interfaces. After database synchronization, the router runs the Dijkstra SPF algorithm on the revised topology map and installs the recalculated shortest paths into the RIB.
Step-by-Step Solution
Key Concept
OSPF Link-State Processing and Convergence Sequence
Estimated Time:1m 30s