Estimate a fleet software upgrade: image transfer, reload time, per-device duration and total elapsed campaign time.
Within a batch the devices are upgraded in parallel, so the campaign length is the number of batches multiplied by the time one device takes rather than the sum over all devices. Only the reload and health-check portion is customer-affecting; the image transfer happens while the device is still in service. Rollouts are planned in change windows of a few hours, and the batch arithmetic is what tells you whether a 120-device fleet is one night's work or six.
Network Upgrade Time
transfer minutes = image MB × 8 ÷ (Mbps × 60); per device = transfer + reload + health check; campaign = batches × per-device time.
transfer minutes = image MB × 8 ÷ (Mbps × 60); per device = transfer + reload + health check; campaign = batches × per-device time. Within a batch the devices are upgraded in parallel, so the campaign length is the number of batches multiplied by the time one device takes rather than the sum over all devices. Only the reload and health-check portion is customer-affecting; the image transfer happens while the device is still in service.
Rollouts are planned in change windows of a few hours, and the batch arithmetic is what tells you whether a 120-device fleet is one night's work or six.
This calculator takes 6 inputs: Devices to upgrade, Software image size, Transfer bandwidth per device, Reload and boot time, Health check per device, Devices upgraded per batch. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.