Cisco Certified Network Associate (CCNA) Practice Exam

In a Frame-Relay network using OSPF, what is the default network type for OSPF interfaces?

1. Broadcast

2. Point-to-point

3. Non-broadcast

4. Point-to-multipoint

The correct answer is: Non-broadcast

In a Frame-Relay network utilizing OSPF (Open Shortest Path First), the default network type for interfaces is classified as non-broadcast multi-access (NBMA). This is due to the nature of Frame-Relay, which does not inherently support broadcast communication. When OSPF is deployed on NBMA networks, it is essential for the OSPF routers to be aware that they will not receive broadcast packets from their neighbors, which influences how they establish adjacencies and exchange routing information. By default, OSPF treats Frame-Relay interfaces as non-broadcast, meaning that routers must manually configure neighbors, as the protocol does not automatically discover them the way it would in a broadcast environment like Ethernet. Understanding this context is crucial because the OSPF behavior in defining network types directly affects the routing and communication between the OSPF routers over the Frame-Relay infrastructure. While other options might represent different network types, they do not accurately reflect the operational characteristics of OSPF on Frame-Relay networks, further establishing the importance of recognizing NBMA as the correct context for this scenario.