PAN-OS collects and sends telemetry data on fixed intervals. Collection is defined on a metric by metric basis, and can be one of:

Telemetry is collected into data bundles. Each bundle is an aggregation of all the data collected up to the point of data transmission. These bundles are stored on the device until a transmission event, which occur once every 1 hour. When a bundle has been successfully sent to Palo Alto Networks, it is deleted from the device.

If an error occurs while sending a bundle to Palo Alto Networks, the firewall waits 10 minutes and then tries again. The firewall will continue to try to send the bundle until it is either successful, or it needs the storage space to collect new telemetry data.

At every regular transmission interval, the firewall begins by sending the bundles scheduled for that event. After a successful transfer of those bundles, the firewall sends any failed bundles that it might have stored from previous transmission events.