Using route aggregation (summary) is one of the important tools with BGP. it provides a strong foundation to keep the routes from flapping, or making rapid changes within the BGP backbone cloud. but what if we want to advertise the aggregation with different AS Path variables? as it is known BGP route can take many variables, from local-preference, weight, as-path, community values, etc.
For that, we have the attribute map a route-map that can be used to set any variable we want to the aggregation. here is the syntax
aggregate-address x.x.x.x x.x.x.x summary-only attribute-map ATTRIB
set community 200:200
set weight 200
it is very simple and effective. hope this post was informative.