Which OSPF message type is used to send the Link-State Advertisements (LSAs) between neighbors?

The OSPF message type that is used to send Link-State Advertisements (LSAs) between neighbors is the Link-State Update message. This message plays a crucial role in the workings of OSPF, as it allows routers to share their link-state information with each other, which is essential for building and maintaining an accurate view of the network topology.

When a router receives Link-State Update messages, it processes the LSAs contained within them and updates its own link-state database accordingly. This ensures that all routers in the OSPF area have a synchronized view of the network, which is necessary for the shortest path calculation used in determining the best routes.

In contrast, other OSPF message types serve different purposes: the Link-State Request is used to solicit specific LSAs from neighbors, the Link-State Acknowledgment confirms the receipt of LSAs, and the Link-State Advertisement describes the LSAs themselves but is not a message type in OSPF like the others. Understanding these distinctions is vital for grasping how OSPF operates and maintains efficient routing within a network.