I am trying to guess what a cellular network provider (or just network provider) would know while using and not using internet.
I am using the term static content for details that don't change often and dynamic content for details that change often. The content in red is which I am not sure whether it is known by the network provider.
1. While I am not using the internet:
The network provider would know Non-internet based static content such as:
personal information including address, occupation, proof of identity, etc (if given/required during purchase)
sensitive personal information including as bank account details, etc,
device details such as IMEI number?, operating system?, type of device (smartphone, tablet etc.)?, MAC address of the device? etc.
[Note: I am not sure whether content such as IMEI number, operating system, type of device (smartphone, tablet etc.), MAC address of the device would come under non-internet based content or internet-based content]
The network provider would know Non-internet based dynamic content such as network-based location (which cell towers I use), call detail records (who you called and when), text message details (who you texted and when), text message content, payment history, etc.
2. While I am using the internet:
The network provider would know Internet-based dynamic content such as IP address, bandwidth consumption, location via GPS (if GPS is turned on), browsing content and history (including the date, time and duration of the internet session)?, the apps running on the device?, data sent and received by the apps?.
3. While I am using the internet via a VPN:
The network provider would know Internet-based dynamic content such as the VPN's IP address, bandwidth consumption, location via GPS?.
(Feel free to comment for any modifications if required for the above details)