Does the SIP protocol have confirmation of the call establishment that the specified subscriber is really trying to call?

Question

SIP

This is a confirmation to the called party that the calling party is actually making the call (and not someone else has specified the calling party's SIP URI).

Something like this:
1) a device with SIP URI [email protected] sends an INVITE to [email protected], where From is set to [email protected], To is set to [email protected];
2) The SIP server on the bob.com domain receives this INVITE, and asks the server on the alice.com domain whether the SIP URI [email protected] from the address from which the INVITE came from actually calls it;
3) if the alice.com server confirms (the user alice is really registered from the specified address), then [email protected]'s phone rings, if not, then the call is rejected.

whether it is provided in the SIP protocol?

Answer 1

No, this is done differently - the client registers on the server, and SIP is wrapped in TLS - thus, we assert trust between the client and the server.
Because in your scheme, no one prevents Alice from specifying the address of the eve.com server, which always confirms that yes, this client is registered and calls through me.