This guide defines and provides debugging steps to identify possible causes of a Session without Data, also known as a Zero-byte Session.
On your device's page, there is a Network Connections in the Last 48 Hours card. In this chart, blue represents data sessions during which data was transmitted. Pink represents closed network sessions without any data transmitted.
Sessions without data, also known as zero-byte sessions, can indicate signaling sessions in proper connection sequence. However, in large volumes, these zero byte sessions generally indicate possible device configuration issues preventing successful data traffic. This is generally caused by one of two issues:
1) The APN is incorrect
A device can attach to a network even if the APN is incorrect. However, the device cannot pass data with an incorrect APN. If the device's APN is incorrect, the device may display zero-byte sessions in your dashboard.
To debug this scenario, confirm that your device's APN is set to hologram.
2) Device firmware issue
A device with many zero-byte sessions in quick succession indicates excessive and unnecessary reconnects. This may be caused by improper connection logic by the device firmware or the cellular module's current configuration. For example, a device constantly trying to connect despite successfully opening data sessions will result in multiple zero-byte sessions over time.
To debug this scenario, audit the device's firmware to ensure that it is programmed to recognize and utilize successful connections. Also confirm that the device's timeout allows for ample time to receive a response message from the network when attempting to open a session.
It may also be helpful to refer to any device-level or network logs from the cellular module because these will provide the most accurate information about your device's behavior.