Pods are a dynamic grouping of video ads to be shown in sequence. Depending on their configuration, they may have a specified maximum number of ads and/or maximum duration for each ad in the pod.
Google Ad Manager's "Optimized pods" require publishers to specify the pod length (either a maximum or an exact duration), allowing them to make a single ad request to receive all eligible ads in one VAST response. Ad Manager optimizes ad decisioning based on the relative value of each ad within the pod.
Pods are supported in VAST 3.0 and later.