Hi my friend,

I would like to test CSFB (Circuit Switched Fallback) using the following test scenarios:

1. A phone on a 2G network sends an SMS to a phone on a 4G network.

2. A phone on a 4G network sends an SMS to a phone on a 2G network.

3. A phone on a 2G network makes a voice call to a phone on a 4G network.

4. A phone on a 4G network makes a voice call to a phone on a 2G network.

Could you please confirm which of the above scenarios should work with CSFB?

If they are supported, I would appreciate guidance on how to test each case in practice.

For my setup, I am using an Osmo-based 2G network, srsRAN for the 4G network, and the Amarisoft LTE Core as the EPC.

Thank you in advance for your support.