CS Fallback problem!!!

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.