Here we have demonstrated each setting of the forwarding mechanism independently by controlling the notification broadcaster. In practice, periodic pulling, agent-side buffering and buffer overflow can all be happening at once. And you can call getNotifications at any time to do an on-demand pull of the notifications in the agent-side buffer. You should adjust the settings to fit the known or predicted behavior of your management architecture, depending upon communication constraints and your acceptable notification loss rate.
The caching policy is completely determined by the manager application. If notification loss is unacceptable, it is the manager's responsibility to configure the mechanism so that they are pulled as often as necessary. Also, the notification mechanism can be updated dynamically. For example, the manager can compute the notification emission rate and update any of the settings (buffer size, pull period, and overflow mode) to minimize the risk of a lost notification.