The convergence cycle used in Link-State Routing Protocols, such as OSFP and IS-IS, differs from that of
the distance-vector protocols. When a router detects a link failure between itself and a neighbor, it tries to
perform a Designated Router (DR) election process on the LAN interface, but fails to reach any neighbors. It
then deletes the route from the routing table, builds a link-state advertisement (LSA) for OSFP or a link-state
PDU (LSP) for IS-IS, and sends it out all other interfaces. Upon receipt of the LSA, the other neighbors that
are up copy the advertisement and forward the LSA packet out all interfaces other than the one upon which
it arrived. All routers, including the router that detected the failure, wait five seconds after receiving the LSA
and run the shortest path first (SPF) algorithm. There after the router that detected the failure adds the new
route to the routing table, while its neighbors update the metric in their routing table. After approximately 30
seconds, the failed router sends an LSA after aging out the topology entry from router that detected the
failure. After five seconds, all routers run the SPF algorithm again and update their routing tables to the path
to the failed link. Convergence time is the total of detection time, plus LSA flooding time, plus the five
seconds wait before the second SPF algorithm is run.