Comprehensive and Detailed in-depth Step-by-Step Explanation:
In OSPF,Link State Advertisements (LSAs)are used to exchange routing and topology information. Each LSA in the OSPF network is uniquely identified using a3-tuple identifier, which consists of:
Link State ID:
The Link State ID uniquely identifies the LSA within the OSPF area. Its value depends on the LSA type. For example, for a Router LSA, the Link State ID is the originating router’s Router ID.
Advertising Router:
This is the Router ID of the router that generated the LSA. It identifies which router is responsible for creating and advertising this LSA.
LSType:
This field identifies the type of LSA (e.g., Router LSA, Network LSA, Summary LSA, AS-External LSA, etc.). It is crucial for interpreting the purpose and content of the LSA.
TheLS Sequence Numberis not part of the 3-tuple that uniquely identifies the LSA. Instead, it is used to determine the most recent version of the LSA in case there are multiple instances of the same LSA.
[References:, Huawei HCIA-Datacom Study Guide, Chapter on "OSPF LSAs and LSDBs"., RFC 2328 – OSPF Version 2 (Section 12.1.6)., , , ]