Dynamic routing protocols are used by routers to facilitate the exchange of routing information between routers.
The purpose of dynamic routing protocols includes: discovery of remote networks, maintaining up-to-date routing information, choosing the best path to destination networks, and ability to find a new best path if the current path is no longer available.
While dynamic routing protocols require less administrative overhead than static routing, they do require dedicating part of a router’s resources for protocol operation, including CPU time and network link bandwidth