High Quality Content by WIKIPEDIA articles! Link State Packet (LSP) is a packet of information generated by a network router in a link state routing protocol that lists the router`s neighbors. Link state packet can also be further defined as special datagrams that determine the names of and the cost or distance to any neighboring routers and associated networks. They are used to efficiently determine what the new neighbor is, if a link failure occurs, and the cost of changing a link if the need arises. LSPs are queued for transmission, and must time out at about the same time. They must be acknowledged, and can be distributed throughout the network, but cannot use the routing database.