Configuring OSPF Neighbor Relationship | Cisco Exam Question

AB.

To configure an OSPF neighbor relationship between R1 and R3 with authentication enabled and connecting interfaces in the same subnet, the next two steps to complete the configuration are:

1. Configure the same process ID for the router OSPF process: D. configure the same process ID for the router OSPF process

OSPF uses a process ID to differentiate between multiple instances of OSPF running on the same router. Each router in an OSPF network must have the same process ID configured to be able to form an adjacency and exchange routing information. Therefore, both R1 and R3 should be configured with the same process ID for OSPF. The process ID is configured in global configuration mode using the "router ospf" command followed by the process ID.

Example:

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R1(config)# router ospf 1 R1(config-router)# 

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R3(config)# router ospf 1 R3(config-router)# 

2. Configure the hello and dead timers to match on both sides: C. configure the hello and dead timers to match on both sides

OSPF uses hello packets to discover and maintain neighbor relationships. The hello packets also carry information such as the router ID, area ID, and OSPF version. The dead interval is the time after which the neighbor is considered dead if no hello packets are received. To form an adjacency, the hello and dead timers on both sides of the link must be the same. By default, the hello interval is 10 seconds and the dead interval is 40 seconds.

Example:

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R1(config)# interface GigabitEthernet0/0 R1(config-if)# ip ospf hello-interval 10 R1(config-if)# ip ospf dead-interval 40 

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R3(config)# interface GigabitEthernet0/0 R3(config-if)# ip ospf hello-interval 10 R3(config-if)# ip ospf dead-interval 40 

Note: Options A, B, and E are not the correct answers because they do not relate to the specific requirements of the question. Configuring the interfaces as OSPF active on both sides (option A) is not necessary because OSPF interfaces are automatically in OSPF active mode by default. Configuring both interfaces with the same area ID (option B) is also not necessary because the question states that the connecting interfaces are already in the same subnet, which means they are already in the same area. Configuring the same router ID on both routing processes (option E) is not necessary because OSPF automatically assigns a router ID based on the highest IP address on a loopback interface or an active interface. If a router ID needs to be manually configured, it should be unique within the OSPF domain.