To verify that an IP-IP tunnel interface is operational, which command should you use?

When verifying the operational status of an IP-IP tunnel interface, the command that provides relevant information about the interface's state, statistics, and configuration details is designed to give insights specifically about IP interfaces.

Using the command that focuses on "ip-0/0/0" allows the administrator to check for various parameters, such as the operational status, whether the interface is up or down, and statistics regarding packets sent and received. This command is particularly important for ensuring that the tunnel is functioning as expected, providing a clear view of IP-related parameters that can help diagnose issues.

In contrast, commands associated with other interface types or non-IP-specific options might not yield the vital information required for IP-IP tunnels. For example, commands specific to ATM interfaces or terse replies that do not focus on IP layers could miss critical details necessary for monitoring the status and performance of the IP tunnel.