What must be included in the subnet definition for a tier?

In utility network design, the correct component to include in the subnet definition for a tier is the valid subnet controllers, including AG (Asset Group) and AT (Asset Type). Subnet controllers play a crucial role in managing how the subnet operates within the broader utility network framework. They help establish the boundaries and functions of the subnet, guiding how the various resources interact and are managed. By specifying valid subnet controllers, the definition ensures that the tier functions correctly within the network, supporting the overall performance and integrity of the utility infrastructure.

When considering other options, while valid resource types are important for identifying elements within the subnet, they do not define operational control. Network performance metrics, although useful for assessing efficiency and effectiveness, are typically not directly specified within the subnet definition itself. Security protocols are vital for data protection and integrity but also do not form a core part of the tier’s subnet definition. Thus, focusing on the valid subnet controllers provides the essential framework necessary for operational effectiveness in utility networks.