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.