Cisco Certified Network Associate (CCNA) Practice Exam

Which interface is set to advertise in area 0 when configuring OSPFv3?

1. Loopback0

2. S0/0

3. Ethernet0

4. S1/0

The correct answer is: S0/0

When configuring OSPFv3, it is important to understand that area 0 is known as the backbone area in OSPF. For an OSPF network to function effectively, it must have a designated backbone area that all other areas connect to. The specified interface that's set to advertise in area 0 typically must be an interfacing point that connects multiple segments or serve as a point of aggregation for OSPF routes. In many cases, serial interfaces (like S0/0) are used to connect different routers within a service provider's infrastructure, or they may connect to another segment of the network. In this scenario, if S0/0 is being used as an interface configured to participate in OSPF operations, it would be responsible for advertising routes to and from area 0. This connection can be crucial for ensuring that routing information from other areas of the network can reach the backbone area, thus allowing OSPF to maintain a coherent and complete routing table across the OSPF domain. The other interfaces listed—Loopback0, Ethernet0, and S1/0—could potentially participate in OSPF but may not be configured to advertise explicitly in area 0 in this particular context. Loopback interfaces are