Cisco Certified Network Associate (CCNA) Practice Exam

Which command sets an OSPF serial interface to a point-to-multipoint network?

1. (config-if)#ip ospf network point-to-point

2. (config-if)#ip ospf network point-to-multipoint

3. (config-if)#ip ospf network broadcast

4. (config-if)#ip ospf network non-broadcast

The correct answer is: (config-if)#ip ospf network point-to-multipoint

The command that sets an OSPF serial interface to a point-to-multipoint network is indeed the one that specifies "point-to-multipoint." This correctly configures the OSPF settings for an interface that connects to multiple endpoints in a network environment where all routers can communicate with each other without the necessity of creating a full mesh topology. In OSPF, a point-to-multipoint configuration allows for more efficient use of bandwidth and simplifies the configuration when multiple routers are connected over a single physical link. It enables these routers to participate in OSPF, sharing routing information as if they were directly connected, which is particularly useful in scenarios such as connecting remote sites back to a central site over a serial link. The other commands listed serve different purposes: the command that designates "point-to-point" focuses on a direct connection between two routers, while "broadcast" and "non-broadcast" configurations target Ethernet-type networks and scenarios where multi-access environments require handling of broadcast traffic differently. Thus, using "point-to-multipoint" in the configuration command is essential for correctly establishing a network where multiple endpoints are managed efficiently within OSPF.