An enterprise router participating in an OSPF area receives a Link-State Update (LSU) packet containing a revised Link-State Advertisement (LSA) from an adjacent neighbor. Arrange the operational steps in the exact chronological sequence the router executes to process the LSA and update its routing table.
- 1Verify the LSU packet header checksum and validate area configuration matching.
- 2Compare the sequence number of the received LSA against the existing entry in the Link-State Database (LSDB).
- 3Store the newer LSA in the local LSDB and flood an LSU copy out all other active OSPF interfaces.
- 4Execute Dijkstra's Shortest Path First (SPF) algorithm using the updated LSDB topology map.
- 5Install the newly calculated optimal routes into the router's Routing Information Base (RIB).
Cevap
The correct operational sequence is: 1) Verify the LSU packet header checksum and validate area matching; 2) Compare the sequence number of the received LSA against the existing entry in the LSDB; 3) Store the newer LSA in the local LSDB and flood an LSU copy out all other active OSPF interfaces; 4) Execute Dijkstra's Shortest Path First (SPF) algorithm; 5) Install the newly calculated optimal routes into the router's RIB.
When a router receives an OSPF Link-State Update (LSU), it first validates packet headers and checksums to ensure packet integrity. Next, it compares the LSA sequence number to verify the update is newer than its existing LSDB entry. Once confirmed, it updates its local LSDB and floods the LSA out other OSPF interfaces to maintain area synchronization. After the LSDB is synchronized, the router executes Dijkstra's SPF algorithm on the updated topology map to calculate shortest path trees. Finally, the resulting shortest paths are installed into the Routing Information Base (RIB).
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OSPF Link-State Update Processing and SPF Recalculation Sequence