Cisco ENCOR Practice Exam 2025 – All-in-One Comprehensive Guide to Mastering Enterprise Network Core Technologies!

Route filtering in OSPF can effectively be implemented using summarization by leveraging the area range command. This command allows network administrators to summarize multiple subnets into a single summary route to be advertised out of an area. By summarizing, OSPF enables the reduction of the number of route entries in the routing table, aiding in more efficient routing.

When you configure OSPF and use the area range command at an Area Border Router (ABR), you can control which routes are advertised from one area to another. The subnets that you are summarizing will be aggregated into a single route, which helps in scenarios where there is no need for every single subnet to be known to all areas. This reduction not only enhances the OSPF design but also minimizes the processing and memory resources on routers, leading to improved network performance.

In contrast, while not-advertise statements can also help manage OSPF route filtering, they are typically more specific in functionality, aiming to prevent particular routes from being propagated rather than employing summarization to achieve broader route aggregation and filtering. Hence, summarization provides a more effective and efficient method for OSPF route filtering in this context.