What is the best way to get a unique call ID?

Question

FreeSWITCH

We have a self-written CRM that allows you to call from the site. There is FreeSwitch, which includes call recording. The problem is that I need to somehow find out the name of the call recording file that FreeSwitch makes in CRM. Now the file name is given like this: call_records/${caller_id_number}/${destination_number}/${strftime(%Y-%m-%d-%H-%M-%S)}.wav
Is there any variable , which contains some unique call identifier so that it is also in the SIP stack, and can it be used in the file name when recording a conversation?

Answer 1

uuid
is not present in SIP, but can be added as an additional header

Answer 2

Callid can be used for this. It is, in fact, a unique call identifier.