Assume you have a carrier that claims they are using SIP Early Offer for call delivery and setup. In addition, assume you have access to network sniffer traces allowing capture of the call setup.

I believe if Early Offer is used, the Invite will include header SDP information about the device initiating the Invite.

How do you confirm that the carrier is actually using Early Offer?

If not, I assume they would use Delayed Offer. If this is correct, how do you confirm the carrier is using Delayed Offer?

Thanks