|  | 11.4 | Link-State Routing
| 11.4.2 |
How link-state protocols exchange routing tables
Network discovery for link-state routing uses the following processes: Routers exchange LSAs with each other. Each router begins with directly connected networks for which it has direct information. Each router in parallel with the others constructs a topological database consisting of all the LSAs from the internetwork. The SPF algorithm computes network reachability. The router constructs this logical topology as a tree, with itself as root, consisting of all possible paths to each network in the link-state protocol internetwork. It then sorts these paths shortest path first (SPF). The router lists its best paths, and the ports to these destination networks, in the routing table. It also maintains other databases of topology elements and status details.