CCNA IP Routing Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Enable IPv6 routing globally with the 'ipv6 unicast-routing' command.

  Why this is correct

  The 'ipv6 unicast-routing' command globally enables IPv6 packet forwarding on the router. OSPFv3 runs directly over IPv6 and requires the router to be capable of forwarding IPv6 traffic; without this command, the router will drop IPv6 packets and cannot establish OSPFv3 adjacencies. This global command is mandatory even if you are only routing internal to a small area.

• ✓

  Create the OSPFv3 routing process using the 'ipv6 router ospf 1' command.

  Why this is correct

  The 'ipv6 router ospf 1' command creates an OSPFv3 routing process and places you in router configuration mode. OSPFv3 uses a process ID that is locally significant, and you must define this process before any interface can be assigned to it. Unlike OSPFv2, OSPFv3 does not use IP network statements; instead, interfaces are enabled directly under the process.

• ✓

  Enter interface configuration mode for the interface that will participate in OSPFv3.

  Why this is correct

  You must enter interface configuration mode for the physical or subinterface that participates in OSPFv3 because OSPFv3 adjacencies are formed per-interface, not per-protocol or per-network. This mode allows you to apply IPv6 enablement and the OSPFv3 area command specifically to that link. Skipping interface mode means no settings can be applied to the actual forwarding hardware.

• ✓

  Enable IPv6 on the interface using the 'ipv6 enable' command, which automatically generates a link-local address.

  Why this is correct

  The 'ipv6 enable' command activates IPv6 on the interface and automatically creates a link-local IPv6 address using EUI-64 format. OSPFv3 uses these link-local addresses as the source for hello packets and as the next hop for routes, so an interface cannot speak OSPFv3 without one. This command is required even if the interface has a global unicast IPv6 address.

• ✓

  Assign the interface to OSPFv3 area 0 using the 'ipv6 ospf 1 area 0' command.

  Why this is correct

  The 'ipv6 ospf 1 area 0' interface subcommand joins that interface to OSPFv3 process 1 within backbone area 0. This directive causes OSPFv3 to begin sending hello packets on that interface toward potential neighbors, and it is how OSPFv3 solves the interface-to-area mapping. Area 0 is the backbone that all other areas must connect through, so this is the typical area for core links.

• ✓

  Verify OSPFv3 neighbor adjacencies with the 'show ospfv3 neighbor' command.

  Why this is correct

  The 'show ospfv3 neighbor' command verifies that OSPFv3 has discovered and established adjacency with neighboring routers by displaying the neighbor Router ID, interface, state, and uptime. An adjacency state of 'Full' indicates that routers have exchanged link-state databases successfully, while '2-Way' means they are just in DROTHER exchange. This command is the key troubleshooting step after configuring OSPFv3 on all participating interfaces.