Answers to Review Questions
1. A is correct. The router ospf 1 command enters router configuration mode for OSPF. It uses the local process ID 1.
2. B is correct. The network 10.10.0.0 0.0.255.255 area 0 command ensures that OSPF runs on any interfaces that have IP addresses that have 10.10 in the first two octets. This is the Gi0/1 interface in this question.
3. D is correct. Neighborships can form in OSPF if one router uses the network command and the other uses the interface-level ip ospf command. Process IDs do not need to match between routers either.
4. D is correct. If you do not manually configure a router ID, the highest IP address on a loopback interface is used as the router ID. If there are no loopback interfaces, the router uses the highest IP address on a physical interface. If OSPF cannot find a configured IPv4 address, the OSPF process does not start.
5. B is correct. The DR and BDR devices are used in the broadcast and non-broadcast network types.