|  | 11.2 | Why Routing Protocols are Necessary
| 11.2.8 | Time to convergence
The routing algorithm is fundamental to dynamic routing. Whenever the topology of a network changes because of growth, reconfiguration, or failure, the network knowledge base must also change. The knowledge needs to reflect an accurate, consistent view of the new topology. This view is called convergence. When all routers in an internetwork are operating with the same knowledge, the internetwork is said to have converged. Fast convergence is a desirable network feature because it reduces the period of time in which routers would continue to make incorrect/wasteful routing decisions.