You are receiving multiple BGP routes from an upstream neighbor and only want to advertise a single summarized prefix to your internal OSPF neighbors. This route should only be advertised when you are receiving these BGP routes from this neighbor.
In this scenario, which type of route should you create?
The requirement is to advertise a single summarized prefix to internal OSPF neighbors only when specific BGP routes are received from an upstream neighbor. A generate route fits this scenario perfectly, as it creates a summary route that is placed into the routing table only when specified contributing routes are active. This ensures that the summary route will only be advertised when the relevant BGP routes are present.
Both aggregate and generated routes would work, but the best choice is generated routes. One key difference... With aggregated routes any prefix in the routing table counts as a contributing route. With generated routes only prefix with a valid next-hop qualifies.
Thanks man, for your explained
C is correct
Aggregate routes are used for advertising summarized network prefixes. They help minimize the number of routing tables in an IP network by consolidating selected multiple routes into a single route advertisement. This approach is in contrast to non-aggregation routing, in which every routing table contains a unique entry for each route. Whereas a generate route: This type of route generates a route that is always present in the routing table and can be used to summarize routes. However, it does not have the capability to only advertise the route when specific BGP routes are being received from a neighbor.