|  | 11.4 | Link-State Routing
| 11.4.1 | Link-state routing basics
The second basic algorithm used for routing is the link-state algorithm. Link-state based routing algorithms, also known as SPF (shortest path first) algorithms, maintain a complex database of topology information. Whereas the distance-vector algorithm has nonspecific information about distant networks and no knowledge of distant routers, a link-state routing algorithm maintains full knowledge of distant routers and how they interconnect. Link-state routing uses: link-state advertisements (LSAs) a topological database the SPF algorithm, and the resulting SPF tree a routing table of paths and ports to each network Engineers have implemented this link-state concept in OSPF (Open Shortest Path First) routing. RFC 1583 contains a description of OSPF link-state concepts and operations.