阅读下面的短文，回答问题
Scope, complexity, and scale of even a single 5G network are massively larger than in today’s networks. The main challenge is automation on all levels of the 5G ecosystem, without it, the network simply will not work; neither for the anticipated scale nor for the desired functional complexity.
Fundamentally, automation is realized by a largely self-governed network bound to varying business goals: its configuration, its services, how they are provided, and how it is managed. A governance model, ideally realized by policies, defines how these goals are implemented and monitored. Those policies can be low-level configuration parameters, mid -level strategies or high-level intents and goals. Using a mix of these-policies implies translation between: top-down for realization and bottom-up for action/benefit and validation purposes.
Networks and models must address multiple, diverse constituencies. Human intervention should be kept to a minimum（oversight）. Management means monitoring and repair; not control. Classic self capabilities are the benefits.
A（ ）model, ideally realized by policies, defines how these goals are implemented and monitored.
