Which of the following is NOT one of the five characteristics of cloud computing according to NIST?

The five characteristics of cloud computing according to the National Institute of Standards and Technology (NIST) include on-demand self-service, resource pooling, rapid elasticity, measured service, and broad network access. On-demand self-service allows users to provision computing capabilities as needed without human intervention from the service provider. Resource pooling refers to the provider's ability to serve multiple consumers using a multi-tenant model. Measured service ensures that the cloud system automatically controls and optimizes resource usage by leveraging a metering capability.

High availability, while an important feature in cloud computing environments, is not defined as one of the five essential characteristics by NIST. Instead, it is a goal that many cloud services strive to achieve as part of their operational reliability and performance but does not inherently define the cloud computing model itself. Therefore, identifying high availability as not being part of the defined characteristics aligns with the NIST framework.