In which phase of the service lifecycle does Service Operation primarily occur?

Service Operation primarily occurs during the phase of the service lifecycle known as Service Transition. This phase is focused on ensuring that new or changed services are effectively transitioned from the development stage into full operational use. It is during Service Operation that the actual delivery and management of services take place, where the primary goal is to ensure that IT services are delivered as intended and that any operational incident or issue is resolved efficiently.

In Service Operation, activities such as incident management, problem management, event management, and access management are executed. These activities are critical for maintaining service quality and ensuring that users receive the services they depend on without unnecessary disruption.

Other phases, such as Service Design, focus on designing new services and making adjustments to existing services in consultation with stakeholders, while Service Delivery is an informal term that does not correspond to a specific stage in the lifecycle as defined by ITIL. Service Improvement, on the other hand, emphasizes continual improvement of services, which is also not exclusively related to the operational aspect but rather looks at overall service effectiveness and efficiency over time. Thus, the most appropriate phase to associate with the ongoing operation of services is the Service Transition stage.