What is the purpose of the OSPF Link-State Update (LSU) packet?

The purpose of the OSPF Link-State Update (LSU) packet is primarily to flood routing information to OSPF neighbors. When a router generates an LSU, it contains information about the router's own links and the state of these links, which is critical for the OSPF routing protocol's operation. By disseminating this information to neighboring routers, LSU packets ensure that all OSPF routers within the same area maintain an accurate and consistent view of the network topology.

This process allows routers to build and update their Link-State Database (LSDB), which is essential for running the OSPF algorithm to compute the shortest path for routing traffic through the network. The flooding mechanism is key to OSPF's ability to quickly adapt to changes in the network, such as link failures or new connections, thus maintaining efficient routing.