Why do large OSPF networks use a hierarchical design? (Choose three.)
正解:B,C,D
Explanation/Reference: Explanation: OSPF implements a two-tier hierarchical routing model that uses a core or backbone tier known as area zero (0). Attached to that backbone via area border routers (ABRs) are a number of secondary tier areas. The hierarchical approach is used to achieve the following: - Rapid convergence because of link and/or switch failures - Deterministic traffic recovery - Scalable and manageable routing hierarchy, reduced routing overhead.