[zakki]

This is how your mobile data traffic is served by your operator:

In 3G/LTE network there are terms called Gn interface, Gi Interface, Gp interface and many others. Gn is to manage your mobility. From Gi you will get local ip address and internet access. From Gp you will be routed to you own cellular operator Gp interface.

When you are on your original cellular operator network, you will be served by Gn and Gi interface for your internet access. When you are roaming, you will be served by Gn and Gp interface of local cellular operator that will forward to your original cellular operator’s Gp. After that it will routed to Gi interface of your original cellular operator.

edited: Gn function