It's called route aggregation or summarization. The problem is that the routing table is not static, but changes constantly. You can't just aggregate once, you

It's called route aggregation or summarization. The problem is that the routing table is not static, but changes constantly. You can't just aggregate once, you'll have to deaggregate and update the routing table with each route update. You also have to be careful that you don't lose information when you aggregate routes, otherwise you'll end up with routing problems.