Aggregate routes are used for advertising summarized network prefixes 1 2 . They help minimize the number of routing tables in an IP network by consolidating selected multiple routes into a single route advertisement 1
. This approach is in contrast to non-aggregation routing, in which every routing table contains a unique entry for each route 1 .
Therefore, option D is correct. Options A, B, and C are not correct because:
* Aggregate routes can be used with both static routing and dynamic routing protocols 1 .
* Aggregate routes are not automatically generated for all of the subnets in a routing table. They need to be manually configured 1 .
* Aggregate routes are not always preferred over more specific routes. The route selection process in Junos OS considers several factors, including route preference and metric, before determining the active route 1 .