Configure special routing filters
Route-maps allow you to more accurately control OSPF and BGP routes redistributions, creating special filters for better route definition, allowing you to customize which route you want to redistribute or import.
Configuration policies are used to control prefix processing by the routing process, and to filter incoming and outgoing ad routes.
Prefixes in incoming and outgoing announcements are filtered using IP route maps, filter lists, IP prefix lists, AS lists, and community lists (BGP).
This precision in controlling your routes allows your routes to be more accurate / efficient, avoiding unnecessary route propagation and optimizing the overall routing.