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everdrive | on: Using eSIMs with devices that only have a physical SIM slot via a 9eSIM SIM car
Does anyone have any resources which explain why eSIMs tunnel your network traffic to the provider? My mental model for old fashioned physical SIMs is that they would roam on the network you're visiting. ie, a Chinese physical SIM on a US network would show up from the US network, and would otherwise be normal except that the phone and network traffic would be very expensive. My understanding of eSIMs is that they act more like a VPN; your network (and phone?) traffic is tunneled back to the home network.
daveoc64 | parent | next
It's not really anything to do with eSIM. If you used a physical SIM from the same carrier with the same settings, you'd have the same experience.

When connecting via a cellular data network, all data will be routed via your carrier's Access Point Name (https://en.wikipedia.org/wiki/Access_Point_Name).

Most carriers only have servers in their home region capable of handling the traffic. It is possible to have regional servers for this, but most carriers don't bother with the expense. Roaming data is usually expensive or restricted in usage - so there's traditionally been very little demand for higher speed connectivity.

Travel eSIMs are usually just a regular SIM with a very limited plan from a carrier that has favourable roaming deals.

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lxgr | parent | next
> My mental model for old fashioned physical SIMs is that they would roam on the network you're visiting.

No, that's never really been the case. It's technically possible (and called "local breakout"), but for various reasons I also don't fully understand, it's usually not done that way.

One is legal liability for user actions; another is accessibility of services at home, such as banking apps, that are probably more comfortable with a familiar IP.

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SSLy | parent
That's not ordered by the SIM but by the packet-core network policies set by both parties.