OSPF
OSPF is an efficient IGP that takes into consideration cost metrics, route speed, traffic levels, link reliability, and security.
OSPF is a link-state routing protocol, which enables it to recalculate routes when topological changes occur.
OSPF only sends a minimal amount of routing traffic, so routers can be updated in a short convergence time.
Convergence time is the time it takes for all routers on the network to have the same routing table information.
Link-state protocols such as OSPF send flooded routing table updates across the network when there is a topology change.
The table updates in link-state routing are first-hand information.