The third step in the link-state routing process is the building of the link-state packet (LSP) containing the state of each directly connected link. It carries the information generated by a network router in a link state routing protocol lists the router’s neighbors. It is a special datagram determining the names of routers including; the cost or distance to any neighboring routers and linked local networks. It can also determine new neighbor In case of link failure. The LSP also determine what the new neighbor is if a link failure occurs, and the cost of changing a link if required.
LSPs are queued for transmission and must time out at about the same time. The network is used to distribute the LSP, but cannot use the routing database. When a router has established adjacencies to other routers, then it can build its LSPs containing the link-state information about its links. Now refer to the figure below the LSP from R1 should contain the information like the following:
R1; FastEthernet network 192.168.0.0/24; Cost 1
R1 -> R2; Serial point-to-point network; 192.168.1.0/24; Cost 1
R1 -> R3; Serial point-to-point network; 192.168.3.0/24; Cost 1