Cisco Certified Network Associate (CCNA) Practice Exam

To configure OSPF on Frame Relay interfaces, how can you resolve the non-broadcast issue?

1. Use static OSPF neighbors.

2. Use subnetting.

3. Enable DHCP on the routers.

4. Change the encapsulation to PPP.

The correct answer is: Use static OSPF neighbors.

When configuring OSPF (Open Shortest Path First) on Frame Relay interfaces, the primary challenge arises from the non-broadcast characteristic of Frame Relay networks. Unlike broadcast-capable networks, where routers can automatically discover each other, non-broadcast networks require manual configuration of OSPF neighbors. Using static OSPF neighbors allows network administrators to explicitly define the routers that can communicate with each other through their specific Frame Relay addresses. This manual configuration is necessary in non-broadcast environments where OSPF cannot automatically establish adjacencies. By specifying the neighboring routers, OSPF can function effectively over Frame Relay links, ensuring that routing information is shared correctly between them. Other options are not suitable for resolving the non-broadcast issue. Subnetting relates to the division of IP address space into smaller segments but does not address the communication problem between routers on a non-broadcast medium. Enabling DHCP is primarily used for dynamically assigning IP addresses, which is unrelated to the OSPF neighbor discovery mechanism. Changing the encapsulation to PPP (Point-to-Point Protocol) might provide a solution since PPP does support dynamic discovery of neighbors, but it is not necessary when static OSPF neighbors can be defined. Thus, using static OSPF