At which NETOPS level is global management of the defense information infrastructure overseen?

The correct answer reflects that global management of the defense information infrastructure is overseen at Tier 1. This tier deals with the highest level of oversight within NETOPS (Network Operations) and is responsible for managing the entire scope of operations and strategic direction across the defense information networks.

Tier 1 focuses on global resource management, strategic planning, and coordination of services and capabilities necessary to ensure the efficient functioning and security of the defense information infrastructure. This includes maintaining awareness of the operational status, security posture, and overall health of the networks.

In contrast, the other tiers such as Tier 2 and Tier 3 tend to focus on more localized management and operational execution, dealing with specific segments of the network and tactical level responses. Tier 4, while also involved in operational aspects, generally pertains to more granular, technical management and troubleshooting rather than overarching global strategies. Therefore, Tier 1 stands out as the correct level for global oversight.